Series 20: The Five Doctors

The Fifth Doctor, Tegan and Turlough are taking a break on the Eye of Orion, one of the most tranquil spots in the universe, when the Fifth Doctor suddenly collapses. Tegan and Turlough bring the Fifth Doctor back into the TARDIS, where they discover to their distress that he is literally fading away. The Fifth Doctor manages to set the TARDIS controls for a destination and the ship dematerializes.

In a hidden chamber, a dark figure is manipulating the controls of a time scoop and kidnapping the Doctor's previous incarnations out of the time stream along with some of his former companions. The First Doctor is taken while he is walking in a rose garden, the Second Doctor and Brigadier Lethbridge-Stewart from a UNIT reunion and the Third Doctor while he is out driving his roadster, Bessie. Also taken out of time are Sarah Jane Smith and the Doctor's granddaughter Susan Foreman. The Fourth Doctor and Romana are taken while punting along the River Cam, but whoever is doing this is frustrated as the two are trapped in the time vortex by a time eddy and unable to rematerialize. All of them, save the Fourth Doctor and Romana, are deposited on a desolate, rocky landscape — the Death Zone on Gallifrey.

Meanwhile, in the Capital on Gallifrey, the High Council of Time Lords, headed by Lord President Borusa and consisting of Chancellor Flavia and the Castellan, watches in concern. The Eye of Harmony is being drained by whoever is taking the Doctor out of time, endangering all of Gallifrey. Despite Borusa's misgivings, the High Council has unanimously voted to call in the Master to assist by going into the Death Zone to help the Doctors. Offered a pardon and a new cycle of regenerations, the Master accepts, and is given a copy of the Seal of the High Council by the Castellan to prove his bona fides, and a matter transmitter (transmat) recall device. He is then teleported via transmat to the Death Zone.

In the Zone, the Doctors face various dangers. The First Doctor and Susan are pursued by a Dalek through a hall of mirrors, finally escaping when they push the Dalek into a dead end, where the discharge of its energy weapon ricochets back and destroys it. The Second Doctor and the Brigadier escape from a squad of Cybermen, and the Third Doctor rescues Sarah from her fall down an embankment. Sarah is mildly confused, as she had seen the Third Doctor regenerate into the Fourth (Planet of the Spiders), but is glad to see the Doctor she once knew. The Second and Third Doctors explain to their companions that in Gallifrey's past, known as the Dark Time, the Time Lords misused their powers. A device called the Time Scoop was used to pluck beings out of their times and place them in the Death Zone, where they would fight each other in a sort of gladiatorial game. The Doctors' goal now is to reach the Dark Tower, where the Time Lord founder Rassilon is entombed, although there is some doubt as to whether Rassilon is actually dead.

The Master meets and tries unsuccessfully to convince the Third Doctor that he is there to help. He is then forced to flee when thunderbolts fall from the sky. The Third Doctor only sees this as confirmation that this is all a plot of the Master's. The First Doctor and Susan find the TARDIS and the presence of the First Doctor seems to stabilize the Fifth for the moment. Together, they scan the tower and find three entrances — one at the apex of the tower, the main gate at the base, and one underground, but a force field prevents the TARDIS's entry. The Fifth Doctor takes Tegan and Susan to go to the main gate, but encounters the Master, who has no better luck convincing the Fifth Doctor than he did the Third. At that moment, the two are surrounded by Cybermen, and when they try to run away, the Master is knocked out by a cybergun blast. The Fifth Doctor finds the Master's recall device on his unconscious body, and transmats himself to the Capitol. The Master, confronted by the Cybermen, offers himself as a guide to the Tower.

In the Capitol, the Doctor is informed of the situation by the High Council. The Doctor realizes not only that he has done the Master an injustice, but also that they were found too easily by the Cybermen. He opens the recall device and finds a homing beacon inside. The Castellan, who gave the Master the device, is arrested and his quarters ordered to be searched. There is found a box containing the Black Scrolls of Rassilon — forbidden knowledge from the Dark Time. Borusa destroys the scrolls before anyone can examine them and orders the Castellan taken to the mind probe for interrogation. However, as the Castellan is escorted outside, there is a shot. The Doctor rushes out to find the Castellan dead, and the Captain of the guard reporting that he was shot while trying to escape. The Doctor voices his concerns to Chancellor Flavia: the Castellan was stubborn, but not a traitor. There is more to this than meets the eye.

The Second Doctor and the Brigadier are exploring a series of caves when they encounter a Yeti left over from the games. Taking refuge in an alcove, the Doctor tries to chase the Yeti off with a firework, succeeding only in maddening it, and causing it to collapse the entrance to the alcove. However, the Doctor detects a breeze from further back and discovers the underground entrance to the Tower.

On the surface, the Third Doctor and Sarah come across a Raston Warrior Robot, according to the Doctor the most perfect killing machine ever devised. Able to move with blinding speed and fire bolts of metal at its targets, it detects its victims by motion. The Doctor and Sarah are unable to move without attracting the robot's attention, but luck is on their side when a squad of Cybermen come over the ridge and are rapidly eliminated by the robot. Taking advantage of the distraction, the Doctor and Sarah run past the robot's position, taking some rope and spare bolts from the robot's cave. Reaching a cliff face just above the Tower, the Doctor uses the rope and bolts to form a grappling hook, and he and Sarah abseil across to the top of the Tower.

Tegan and Susan have told the First Doctor what happened to the Fifth Doctor. The First Doctor decides to head for the main gate himself, with Tegan insisting on accompanying him. Opening the main gate through the means of a keypad hidden under a bell, they find a chessboard floor pattern blocking their way. The First Doctor determines that the chessboard is a trap — electrical bolts will destroy anyone attempting to cross unless they find the safe path. The Master appears at this point, warning them that the Cybermen are close behind. While the Doctor and Tegan hide, the Master lures the Cybermen onto the chessboard where they are killed. The Master tells the Doctor, "It's as easy as pie", then blithely steps across the board and moves into the Tower. The Doctor realizes that the Master means the Greek letter pi, and that the safe path is calculated by means of the mathematical constant. He and Tegan make their way across the trap. In the Zone, the TARDIS is being surrounded by Cybermen who start to assemble a bomb to blow it up. Inside, Turlough and Susan watch helplessly.

The Second and Third Doctors encounter more obstacles while moving separately through the Tower, with the mind of Rassilon exuding an intensifying feeling of fear. They also encounter what appear to be their previous companions: the Third meeting Captain Mike Yates and Liz Shaw; the Second meeting Jamie McCrimmon and Zoe Heriot. The Doctors soon realize that the 'companions' are just phantoms designed to impede their progress through the Tower, and the spectres vanish with a scream. Finally, all three Doctors reach the tomb where Rassilon's casket lies. While the Brigadier, Sarah, and Tegan get re-acquainted, the three Doctors try to translate an inscription written in Ancient Gallifreyan on a pedestal near a control panel.

The Fifth Doctor finds that Borusa has vanished from the Council chamber, but the guards insist that the President could not have gotten by them at the only entrance. The transmat is out of power, so the Doctor deduces that there must be a secret door. He finds it hidden behind a painting of Rassilon playing the harp. The key to opening the door is a series of notes played on the actual harp standing before the painting — notes indicated by the sheet music in the painting itself. The Doctor enters the secret chamber, finding the dark figure that had taken his other selves out of time: Borusa. The Lord President is not satisfied with ruling Gallifrey for his lifetimes — he wants to be President Eternal. Borusa has determined that Rassilon discovered the secret of immortality, and he means to claim it, sending the Doctors into the Zone to clear the way for him. Using the Coronet of Rassilon, Borusa overwhelms the Fifth Doctor's will, thus forcing the latter to obey his commands.

In the tomb, the Doctors have deciphered the inscription: Rassilon had discovered immortality and will share it with whomever overcomes the obstacles to the tomb and takes the ring from his body. However, one line troubles the First Doctor: "To lose is to win and he who wins shall lose." The Master steps out of the shadows to claim immortality for himself, yet is jumped from behind by the Brigadier and tied up by Sarah and Tegan. The Third Doctor fixes the control panel by reversing the polarity of the neutron flow, allowing the TARDIS to transport itself to the tomb (just seconds before the Cybermen's bomb detonates).

The Second Doctor contacts the Capitol and the Fifth Doctor answers, still under Borusa's control. He tells his other selves to await their arrival. He and Borusa transmat over to the tomb. Borusa paralyzes the Doctors' companions with a command and tries to control the minds of the Doctors as well, but fails as all four Doctors combine their wills against him. However, a booming voice echoes through the chamber — the voice of Rassilon, demanding to know who disturbs him. Borusa steps forward to claim immortality and while the other Doctors protest, the First Doctor holds the others back and says to the projection of Rassilon that Borusa deserves the prize. Borusa takes the ring from the body and puts it on. He finds himself paralyzed, then transformed into one of several stone faces carved into the side of the casket. Rassilon sends the Master back to his own time, then frees the Fourth Doctor from the time vortex and returns to eternal rest. The First Doctor smugly tells the Fifth that he finally understood the proverb. The 'prize' was yet another trap — a means for Rassilon to eliminate whoever sought immortality.

The Doctors and the companions say their good-byes to each other and re-enter the TARDIS save for the Fifth Doctor, Tegan, and Turlough. As those three watch, the others are transported back to their proper times. Chancellor Flavia arrives with guards and tells the Doctor that with Borusa's disappearance, the Council has appointed the Doctor as President. The Doctor appears reluctant, but Flavia tells him he cannot refuse an order of the Council or it will attract the severest penalties. The Doctor orders Flavia back to the Capitol, saying that he will travel there in his TARDIS and that she has full powers until his return. Once in the TARDIS, though, he reveals to Tegan and Turlough that he has no intention of returning. Tegan asks if the Doctor really intends to go on the run from his own people in a rickety old TARDIS. The Doctor replies, smiling, "Why not? After all, that's how it all started."

Cast
Doctor Peter Davison (Fifth Doctor)
Richard Hurndall (First Doctor)
Patrick Troughton (Second Doctor)
Jon Pertwee (Third Doctor)
Tom Baker (Fourth Doctor, previously untransmitted archive footage only)
William Hartnell (First Doctor, pre-titles archive footage clip only)
Companion Janet Fielding (Tegan Jovanka)
Mark Strickson (Vislor Turlough)
Carole Ann Ford (Susan Foreman)
Elisabeth Sladen (Sarah Jane Smith)
Lalla Ward (Romana II, previously untransmitted archive footage only)
Guest stars
Nicholas Courtney — The Brigadier
Anthony Ainley — The Master
Philip Latham — Lord President Borusa
Dinah Sheridan — Chancellor Flavia
Paul Jerricho — The Castellan
David Banks — Cyber Leader
Mark Hardy — Cyber Lieutenant
Richard Mathews — Rassilon
Frazer Hines — Jamie
Wendy Padbury — Zoe
David Savile — Colonel Crichton
Caroline John — Liz Shaw
Richard Franklin — Captain Yates
John Leeson — Voice of K9
Roy Skelton — Dalek Voice
John Scott Martin — Dalek Operator
Ray Float — Sergeant
Keith Hodiak — Raston Robot
Stuart Blake — Commander
Stephen Meredith — Technician
John Tallents — Guard
William Kenton — Cyber Scout

Production
Writer Terrance Dicks
Terry Nation (The Dalek Invasion of Earth segment) (uncredited)
Douglas Adams (Shada segments) (uncredited)
Director Peter Moffatt
John Nathan-Turner (uncredited)
Richard Martin (The Dalek Invasion of Earth segment) (uncredited)
Pennant Roberts (Shada segments) (uncredited)
Script editor Eric Saward
Producer John Nathan-Turner
Executive producer(s) None
Production code 6K
Series Season 20
Length 90 minutes
Originally broadcast November 23, 1983 (first global)
November 25, 1983 (first UK)

source: wikipedia

Series 20: The King's Demons

In 1215, the Court of King John of England is at the castle of Sir Ranulf Fitzwilliam to extort more taxes, and when the lord refuses to pay the King insults him. To defend his honour his son Hugh takes on the King’s champion, Sir Gilles Estram, in a joust. The latter wins easily, though the joust is disturbed by the arrival of the TARDIS. The Doctor, Tegan, and Turlough are greeted as demons and welcomed by the King.

Having established the date, the Doctor concludes the King is not himself - in fact, he is not the King at all, as he is actually in London taking the Crusader’s Oath. Sir Geoffrey de Lacy, the cousin of Sir Ranulf, arrives at the castle and confirms he knows the King is in London. Sir Gilles is about to torture him as a liar during a royal banquet when the Doctor intervenes. It seems the King's champion is not who he claims to be, either: Sir Gilles sheds his disguise and reveals himself to be the Doctor’s arch nemesis, the Master. He flees in his own TARDIS, which had been disguised as an iron maiden.

The King knights the Doctor as his new champion, and he is given run of the castle. After a series of mishaps, including the death of Sir Geoffrey at the Master’s hands, the Doctor confronts the King and the Master and discovers the truth. The monarch is really Kamelion, a war weapon found by the Master on Xeriphas, which can be mentally controlled and used to adopt disguises and personas. Disguised as King John, the Master intends that Kamelion will behave so appallingly so as to provoke a rebellion and topple the real King from his throne, thus robbing the world of Magna Carta, the foundation of parliamentary democracy. It is a small plan on the Master’s usual scale, but nevertheless particularly poisonous to the normal progress of Earth society.

The Doctor resolves the situation by testing the Master in a battle of wills for control over Kamelion. He takes control of the robot and steals it away in the TARDIS, thus foiling the Master’s scheme. Kamelion reverts to its robot form and thanks the Doctor for his assistance and rescue.

Cast
Doctor Peter Davison (Fifth Doctor)
Companions Janet Fielding (Tegan Jovanka)
Mark Strickson (Vislor Turlough)
Gerald Flood (Kamelion)
Guest stars
Anthony Ainley — The Master / Sir Gilles Estram
Gerald Flood — King John
Frank Windsor — Ranulf
Isla Blair — Isabella
Christopher Villiers — Hugh
Michael J. Jackson — Sir Geoffrey de Lacey
Peter Burroughs — Jester

Production
Writer Terence Dudley
Director Tony Virgo
Script editor Eric Saward
Producer John Nathan-Turner
Executive producer(s) None
Production code 6J
Series Season 20
Length 2 episodes, 25 minutes each
Originally broadcast March 15–March 16, 1983

source: wikipedia

Series 20: Enlightenment

Part One
The White Guardian appears in the TARDIS, warning the Fifth Doctor of great danger and giving him a set of co-ordinates. Before the White Guardian can explain further, the Black Guardian appears and interrupts the communication. The Doctor sets the co-ordinates and the TARDIS materializes in what appears to be a ship's hold. Leaving Tegan in the TARDIS in case the White Guardian tries to contact them again, the Doctor and Turlough leave to explore, barely avoiding one of the officers, dressed in an Edwardian naval uniform and having a mechanical, blank expression.

Speaking with the crew, the Doctor discovers they remember nothing of coming aboard, have been below decks the whole time, and that the ship they are on has been entered in some sort of race. Meanwhile, Tegan leaves the TARDIS and encounters the ship's first mate, Marriner, who offers to take her to her friends, whom he knows about even though he's not met them yet. An officer with the same distant look escorts the Doctor to see Captain Striker, who offers them dinner. However, the dinner is interrupted when the wind picks up and the officers announce that the race has begun. Going to the wheelhouse, the Doctor sees a map of the race course, complete with "marker buoys" which he recognizes as the planets of Earth's solar system. Marriner then operates anachronistic electronic controls and a viewscreen activates to show the other contestants - a Greek trireme, a 17th Century pirate ship, and other vessels from other times, all floating in deep space and using solar winds for propulsion.


Part Two
The Doctor speaks to Striker and discovers that he and his officers are Eternals, beings who live in the "trackless wastes of eternity," as opposed to the Doctor and his companions, who are "Ephemerals." As the ships round Venus, the trireme captained by Critas the Greek explodes when it tries to overtake the pirate ship. Striker believes that it was the gravitational pull that did it, but the Doctor suspects otherwise. Tegan feels ill, so Marriner escorts her to a room which she soon realizes is a mixture of her room in the TARDIS and her rooms in Brisbane - they have been reading her mind. Marriner seems quite taken by Tegan, finding her mind fascinating and full of life.

In conversation with Striker, the Doctor finds out that Eternals use Ephemerals for their thoughts and ideas. The Eternals have lived for so long that they are unable to think for themselves and need human minds to give them existence, and entertainment — that is why the ships use human crews. The purpose of the race, however, is more than entertainment. The prize is Enlightenment, the wisdom to know everything. The TARDIS is discovered by the Eternals, who make it vanish. Trapped on board the Edwardian ship for the moment, the Doctor and his companions go on board deck in space suits. Turlough hears the voice of the Black Guardian taunting him and unable to take the strain, he leaps overboard into space.


Part Three
Turlough is rescued by the Buccaneer, the pirate ship commanded by Captain Wrack. She toys with Turlough sadistically with a knife, but he manages to convince her that he jumped overboard to throw in his lot with her, to find out the secret of how she will win the race. Wrack sends her first mate to present Captain Davey (one of the other competitors) with a jewelled sword, and to deliver party invitations to the other captains. On board the Edwardian ship, Striker refuses the invitation, but the Doctor accepts, wanting to retrieve Turlough. Marriner offers to escort Tegan and the Doctor to the Buccaneer as an asteroid storm hits the ships. As Davey's ship draws level with the Buccaneer, Wrack takes Turlough down in the hold and shows him the entrance to a locked chamber with a vacuum shield, but leaves him outside when she enters. Through the door, however, Turlough hears the voice of the Black Guardian as Davey's ship explodes, apparently hit by an asteroid. The Doctor, though, again suspects otherwise, especially since like Critas's ship, Davey was also challenging the Buccaneer.

Arriving on board the Buccaneer for the party, the Doctor and Tegan mingle while Turlough sneaks off to examine the locked chamber. He finds an eye-shaped grid open to space, but a pirate locks the door and turns off the vacuum shield. Fortunately, the Doctor finds Turlough before he suffocates. The Doctor then notices the eye-shaped projector above the grid, and theorizes that this must be how Wrack transmits the power to destroy the other ships, using some sort of focus. He remembers Critas was wearing an out-of-period clasp with a red crystal, and Turlough tells him of Wrack's gift to Davey and the Doctor realizes the red crystal is the focus. Before they can act on it, however, they are captured by Wrack's first mate. Meanwhile, Wrack has managed to lure Tegan away from the party to her wheelhouse and freezes her in time while she plants a red crystal in her tiara.


Part Four
Brought before Wrack, Turlough accuses the Doctor of being a spy and claims he was trying to capture the Doctor. Wrack sends the Doctor, Tegan and Marriner back to the Edwardian ship. The Doctor believes that Turlough is trying to prove himself trustworthy by stopping Wrack. Unfortunately, Wrack sees into Turlough's mind and is about to sentence him to walk the plank. She pauses, however, when Turlough tells her that he, too, serves the Black Guardian. As the ships near the crystalline space station of the Enlighteners, the Buccaneer pulls level with the Edwardian Ship, and Wrack brings Turlough once again to the chamber, this time letting him witness her summoning the power of the Black Guardian. The Doctor, seeing the Buccaneer pull close, realizes that the focus must have been smuggled aboard somehow, and as he describes it, Tegan tells him about the crystal in the tiara. The Doctor smashes the crystal, but only manages to multiply the power by the number of fragments.

The Doctor gathers up the pieces, rushing up to the deck and just in time hurls them overboard as they explode. Suddenly, the wind dies, and Wrack pulls ahead of the Edwardian ship. The Doctor demands that the TARDIS be released to him to stop Wrack from winning, and Marriner reveals that it was concealed within the Doctor's own mind. Travelling in it to the Buccaneer, the Doctor tries to reason with Wrack, but her first mate shows up with Turlough, and she orders that the Doctor be thrown into space. As Tegan watches from the Edwardian ship, two bodies are ejected into space, and the Buccaneer reaches the finish. The human crew of the Buccaneer vanish as Tegan, Striker and Marriner board to give their respects to the victor.

The Enlighteners turn out to be the Black and White Guardians, and the winner is the Doctor, who brought the ship in with Turlough's help when Wrack and her first mate met with an "accident." The Doctor, however, refuses the diamond crystal containing Enlightenment, saying that he's not ready for it, and the White Guardian dismisses Striker and Marriner, who vanish back into eternity. As Turlough helped the Doctor bring the ship in, he is entitled to a portion of the prize. The Black Guardian reminds Turlough of their bargain, and says that he can give up the diamond, or sacrifice the Doctor to gain both Enlightenment and the TARDIS. Turlough struggles with a decision, and hurls the diamond at the Black Guardian, who vanishes in screams and flames. The Doctor points out that Enlightenment was not the diamond, but the choice itself. The White Guardian warns once again that the Black Guardian will return, even angrier now that he has been thwarted twice, and vanishes himself. Turlough asks the Doctor to take him back to his home planet, and the Doctor agrees.

Cast
Doctor Peter Davison (Fifth Doctor)
Companions Janet Fielding (Tegan Jovanka)
Mark Strickson (Vislor Turlough)
Guest stars
Cyril Luckham — White Guardian
Valentine Dyall — Black Guardian
Keith Barron — Striker
Christopher Brown — Marriner
Lynda Baron — Wrack
Leee John — Mansell
James McClure — First Officer
Tony Caunter — Jackson
Clive Kneller — Collier

Production
Writer Barbara Clegg
Director Fiona Cumming
Script editor Eric Saward
Producer John Nathan-Turner
Executive producer(s) None
Production code 6H
Series Season 20
Length 4 episodes, 25 minutes each
Originally broadcast March 1, 1983 – March 9, 1983

source: wikipedia

Series 20: Terminus

Under the Black Guardian's instructions, Turlough sabotages the TARDIS, causing parts of it to dissolve. As the field of instability threatens to engulf Nyssa's room, a door appears behind her and the Fifth Doctor tells her to go through it. The TARDIS, to save itself, has materialized aboard a spaceship heading for an unknown destination. The Doctor and Nyssa, while exploring the ship, encounter two raiders, Kari and Olvir, who are intent on plundering the ship's cargo.

When the raiders' ship abandons Kari and Olvir, it becomes apparent that the spaceship is actually a transport carrying lazars, sufferers of a leprosy-like disease, to a space station named Terminus. The station is owned by Terminus, Inc., which claims that a cure exists there, but no-one has returned from it. Nyssa, separated from the Doctor, is infected by Lazar's Disease and ushered away with the rest of the lazars. Terminus is manned by the Vanir, guards clad in ornate radiation armor. They are slave labour, kept alive only by regular doses of a drug called hydromel, which is supplied by the corporation.

The Doctor discovers that Terminus is at the centre of the known universe and finds this information unsettling. Nyssa, meanwhile, is given over to the Garm, a giant dog-like biped, who takes her to a chamber and exposes her to radiation. The Doctor and Kari find the control room of Terminus and he realizes that Terminus is also a time ship. In some unspecified past, the fuel that powered Terminus became unstable and the now dead pilot had tried to jettison it while still in the time vortex. The tank exploded, and the outrush of energy started Event One - the Big Bang - and hurled Terminus billions of years in the future. There is still one tank of unstable fuel left, and the computer has begun a countdown to jettison that too. However, where the first explosion created the universe, the second will undoubtedly destroy it.

Nyssa awakes to find out that she is no longer infected. The radiation cure works, but it is haphazard, with as many people dying from it as recovering. The Garm knows this, but is unable to refine it as he is controlled by the Vanir. Enlisting the Garm's help, the Doctor staves off the countdown long enough to disable the computer and cut the engine control wires. In return, the Doctor destroys the electronic control box, setting the Garm free.

Nyssa strikes a bargain with the Vanir - in exchange for synthesizing hydromel and freeing them from the corporation's influence, they will turn Terminus from a leper colony into a true hospital, and with the Garm's help refine the radiation cure. Deciding that her scientific skills are needed more on Terminus, Nyssa elects to stay behind, bidding her friends a tearful farewell. As Tegan and the Doctor return to the TARDIS, the Black Guardian tells Turlough that this is his last chance to kill the Doctor...

Cast
Doctor Peter Davison (Fifth Doctor)
Companions Sarah Sutton (Nyssa)
Janet Fielding (Tegan Jovanka)
Mark Strickson (Vislor Turlough)
Guest stars
Valentine Dyall — Black Guardian
Liza Goddard — Kari
Dominic Guard — Olvir
Andrew Burt — Valgard
Tim Munro — Sigurd
Martin Potter — Eirak
Peter Benson — Bor
R.J. Bell — The Garm
Martin Muncaster — Tannoy Voice
Rachel Weaver — Inga

Production
Writer Stephen Gallagher
Director Mary Ridge
Script editor Eric Saward
Producer John Nathan-Turner
Executive producer(s) None
Production code 6G
Series Season 20
Length 4 episodes, 25 minutes each
Originally broadcast February 15, 1983 – February 23, 1983

source: wikipedia

Series 20: Mawdryn Undead

In 1983, the former Brigadier Lethbridge-Stewart teaches mathematics at Brendon Public School, where Turlough is a student. In the aftermath of a car accident in which Turlough and another student take the Brigadier's classic car for a joyride and crash, Turlough is contacted by the sinister Black Guardian, whom the Doctor thwarted during the quest for the Key to Time. Seeking revenge, the Black Guardian offers Turlough transportation off Earth if he will kill the Doctor.

Meanwhile, the Fifth Doctor, Tegan and Nyssa have problems of their own. The TARDIS is caught in a warp ellipse and materialises on board a starliner locked in a perpetual orbit in time and space. Turlough, under the Black Guardian's instructions, transports himself onto the liner from Earth by means of a transmat capsule and encounters the TARDIS crew. The Doctor travels to Earth via transmat, taking Turlough with him, to get rid of the transmat interference that is trapping the TARDIS on the liner. Unfortunately, when the TARDIS tries to materialize on Earth, it vanishes. The Doctor meets the Brigadier at the Brendon school, but is puzzled when his old comrade-in-arms does not remember their time together at first. When the Doctor says he has to find Tegan and his TARDIS, the Brigadier remembers meeting her in 1977. The Doctor realizes that the TARDIS is right there - just six years earlier - and tries to get the Brigadier to remember the events that led to his nervous breakdown in 1977.

In 1977, Tegan and Nyssa encounter the transmat capsule, but inside is an alien-looking humanoid whom they initially believe is the Doctor, horribly injured. Meeting the younger Brigadier, they bring him and the alien back to the starliner, which is actually the prison of a group of alien scientists who had been trying to discover the Time Lord secret of regeneration. As Mawdryn, the leader of the group explains, they only succeeded in trapping themselves in a cycle of perpetual mutation and regeneration and now long for death. When the Doctor finds out that there are two Brigadiers aboard, he has to try to keep the two apart lest the resulting energy discharge prove catastrophic.

Trying to leave in the TARDIS, the Doctor discovers that Tegan and Nyssa have been infected by the same malady as Mawdryn and his compatriots. The only cure, it seems, is to do what Mawdryn demands: the Doctor must give up the energy from his remaining regenerations. Hooking himself up to Mawdryn's apparatus, the Doctor is about to sacrifice himself when the two Brigadiers meet and touch hands, causing a discharge of temporal energy at precisely the right instant. Tegan and Nyssa are cured, the alien scientists succeed in ending their undead existence, and the Doctor remains a Time Lord. The younger Brigadier, however, will not remember his time with the Doctor until they meet again in 1983...

After returning the Brigadiers to their respective time zones, Turlough asks if he can join the Doctor in his travels. The Doctor agrees, apparently not realizing he is taking an assassin into the fold.

Cast
Doctor Peter Davison (Fifth Doctor)
Companions Sarah Sutton (Nyssa)
Janet Fielding (Tegan Jovanka)
Mark Strickson (Vislor Turlough)
Guest stars
Nicholas Courtney — The Brigadier
David Collings — Mawdryn
Valentine Dyall — Black Guardian
Angus MacKay — Headmaster
Stephen Garlick — Ibbotson
Roger Hammond — Dr Runciman
Sheila Gill — Matron
Peter Walmsley, Brian Darnley — Mutants

Production
Writer Peter Grimwade
Director Peter Moffatt
Script editor Eric Saward
Producer John Nathan-Turner
Executive producer(s) None
Production code 6F
Series Season 20
Length 4 episodes, 25 minutes each
Originally broadcast February 1–February 9, 1983

source: wikipedia

Series 20: Snakedance

The arrival of the TARDIS on Manussa, formerly homeworld of the Manussan Empire (destroyed) and Sumaran Empire (destroyed), triggers nightmares in Tegan, who dreams of a snake-shaped cave mouth. It is evident to the Fifth Doctor that the Mara is reasserting itself on her mind following her possession by the entity while on the Kinda planet of Deva Loka. He attempts to calm her by taking her and Nyssa in search of the cave but Tegan is too scared to enter when they find it, and runs away. Alone and confused Tegan lapses under the control of the Mara once more, revelling in horror and destruction. The emblem of the snake soon returns to her arm.

Manussa is in the grip of a festival of celebration of the banishment of the Mara from the civilisation five hundred years earlier. In the absence of the Federator, who rules over a the three-planet Federation, his indolent son Lon is to have a major role in the celebration, supported by his mother the Lady Tanha and the archaeologist Ambril, who is an expert in the Sumaran period. Lon is intrigued with the notion that the Mara might one day return as prophesied, but Ambril is unconvinced and believes such talk is the product of cranks. When the Doctor tries to get Ambril to take the threat seriously he too is dismissed as a maverick, though the deputy curator Chela is more sympathetic to the Doctor and gives him a small blue crystal called a Little Mind's Eye, which is used by the Snakedancers, a mystical cult, in their ceremonies to repel the Mara. The Doctor realises the small crystal and its large counterpart, the Great Mind's Eye, can be used as focal points for mental energy and can turn thought into matter. This, he determines, is how the Mara will transfer from Tegan's mind to corporeal existence. He realises that the Manussans must once have been a very advanced people who could use molecular engineering in a zero-gravity environment. They created the Great Mind's Eye without realising its full potential, and the crystal drew the fear, hatred, and evil from their minds, amplified it and fed it back to them. Thus the Mara was born into Manussa and the reign of the Sumaran Empire began.

Meanwhile Tegan makes contact with Lon and passes the snake mark of the Mara to him too. They visit the cave from Tegan's dream which contains a wall pattern which could accommodate the Great Crystal. Lon is sent back to the Palace while she causes more havoc and takes control of a showman, Dugdale, who is used for her pleasure. Lon meanwhile covers his arm and goes about trying to persuade Ambril to use the real Great crystal in the ceremony, placing it in a position in a wall carving that will evidently enable the Mara to return as the Doctor predicted. To persuade him to comply, Ambril is shown a secret cave of Sumaran archaeological treasures and warned they will all be destroyed if he does not help him. Ambril thus agrees to the change in format.

The Doctor and Nyssa have meanwhile been aided by Chela, who shares with them the journal of Dojjen, a snakedancer who was Ambril's predecessor. All three venture to the Palace to persuade the authorities to do something about the situation, but soon see Lon is in the grip of the Mara and orchestrating a very dangerous situation. All three escape and the Doctor now uses the Little Mind's Eye to contact Dojjen, who lives in sandy dunes beyond the city. They venture there and the Doctor communes with Dojjen by opening his mind after being bitten by a poisonous snake. He is told by the wise old snakedancer that the Mara may only be defeated by finding a still point in the mind. All three now head back to the city to prevent the ceremony of defeating the Mara using the real Great Crystal. The festivities are now at a peak, with a procession taking place which culminates in a ceremony at the cave. Lon plays the role of his ancestor Federator in rejecting the Mara. After a series of verbal challenges he seizes the real Great Crystal and places it in the appropriate place on the wall. Tegan and Dugdale arrive and she displays the Mara mark on her arm, which is now becoming flesh having fed on the fear in Dugdale's mind. With the crystal in place, the Mara is able to create itself in the cave, becoming a vast and deadly snake. However, the Doctor arrives in time and refuses to look at the snake or recognise its evil, relying instead on the still place he finds through mental commune with Dojjen via the Little Mind's Eye. This resistance interrupts the manifestation of the Mara and its three slaves are freed while the snake itself dies and rots. The Doctor comforts a distraught Tegan, sure that the Mara has at last been destroyed.

Cast
Doctor Peter Davison (Fifth Doctor)
Companions Sarah Sutton (Nyssa)
Janet Fielding (Tegan Jovanka)
Guest stars
Martin Clunes — Lon
Colette O'Neil — Tanha
John Carson — Ambril
Preston Lockwood— Dojjen
Jonathon Morris — Chela
Brian Miller — Dugdale
George Ballantine — Hawker
Brian Grellis — Megaphone Man
Barry Smith — Puppeteer
Hilary Sesta — Fortune Teller

Production
Writer Christopher Bailey
Director Fiona Cumming
Script editor Eric Saward
Producer John Nathan-Turner
Executive producer(s) None
Production code 6D
Series Season 20
Length 4 episodes, 25 minutes each
Originally broadcast January 18–January 26, 1983

source: wikipedia

Series 20: Arc of Infinity

On Gallifrey a Time Lord traitor is at work stealing the bio-data code of another Time Lord and killing a technician who stumbles across the crime. The traitor provides the bio-data to a creature known as the Renegade, which is composed of anti-matter and uses the bio-data to invade the TARDIS and then the Doctor's metabolism. His companion, Nyssa, helps him recover. The Renegade is shielded in this attempt by the Arc of Infinity, a curious curve between the dimensions containing quad radiation which can shield anti-matter. The Doctor decides to head to Gallifrey to track down the supplier of his bio-data, conscious that unless the creature trying to cross universes is stopped that its incursion could cause a fatal chain reaction to our universe.

The High Council of the Time Lords is also taking the matter seriously and has decreed that the Doctor’s TARDIS should be recalled for the same reason. The Chancellery Guard under the over-zealous Commander Maxil seizes the Doctor and Nyssa. He stuns the Doctor to ensure his delivery to the High Council. When the Doctor is brought before the High Council the new Lord President, Borusa, is inscrutable while Chancellor Thalia and Cardinal Zorac are openly hostile; only his old friend Councillor Hedin seems pleased to see him. The President stresses the gravity of the situation since the Renegade poses such a threat to the Universe, and the High Council has had no alternative but to issue a Warrant of Termination on the Doctor to ensure the Renegade can no longer bond with him. The Doctor is taken away protesting, sure his bio-data has been compromised and stolen from within the High Council. Fortunately an old friend, Damon, who is another technician in the records section, provides him with the proof he needs that a member of the High Council did indeed steal his bio-data extract. The Doctor is soon taken for execution, despite Nyssa’s attempts to save him, and placed in a dispersal chamber. Sentence is carried out.

The supposed death of the Doctor, however, has not solved the situation. Unbeknownst to the High Council, his mind has been taken into the Time Lord living repository of knowledge, the Matrix, while his body is hidden behind a force shield in the termination cubicle. The Renegade, who demands an opportunity to return to the Universe it once inhabited, contacts him. The truth of the aborted execution is discovered by the wily Castellan, who tells first Nyssa and Damon that the Doctor is alive; and then the High Council.

Meanwhile in Amsterdam, Netherlands the Doctor’s former companion Tegan Jovanka arrives looking for her cousin Colin Frazer. She is greeted by his friend Robin Stuart who explains that Colin has disappeared while they were crashing in the crypt of the Frankendael mansion. When neither of them can persuade the police to take an interest they decide to investigate the crypt themselves. They find a hypnotised Colin working for a curious birdlike creature which is armed with a deadly weapon. They are rendered unconscious and their minds scanned, revealing to the Renegade, who has established its base in a TARDIS hidden at the Frankendael, that Tegan knows the Doctor. The Renegade uses Tegan as bait to force the Doctor to obey him, also releasing Colin from his slavery as a reward. The Doctor is returned to normal space on Gallifrey where he makes for the High Council Chamber. Lord President Borusa has fallen under suspicion of being a traitor because the Castellan reveals it was his codes that were used to transmit the bio-data. The truth, however, is that Councillor Hedin is the Time Lord in league with the Renegade. He is in awe of his master - the mighty Omega, first of the Time Lords and pioneer of time travel (see The Three Doctors). Hedin wishes to release Omega from his exile in a universe of anti-matter, not realising the great Time Lord has been driven mad by his years of solitary confinement. The Castellan kills Hedin, but this does not prevent Omega using the Arc of Infinity to seize total control of the Matrix and, therefore, the organisation of Gallifrey.

Fortunately the Doctor and Nyssa manage to slip away and return to the TARDIS. They use scant knowledge provided by Tegan to determine that Omega has established its base in Amsterdam on Earth, and head there immediately, desperately trying to find the Frankendael crypt she described. After a lengthy hunt they find the lair defended by the birdlike creature, the Ergon, and Nyssa disposes of it with its own matter-converter gun. They reach Omega’s TARDIS at the point at which both the ship is destroyed and Omega makes full transference to Earth using the arc of infinity. When he peels his decayed mask away he reveals the features of the Doctor. Omega heads off into Amsterdam with the Doctor and Nyssa in hot pursuit. Within a short time the Doctor’s prediction of an unstable transfer begins to come true: Omega’s flesh decays and it his clear his new body is not permanent. When the Doctor and Nyssa catch up with him it is a painful task for the Doctor to use the Ergon’s anti-matter converter on Omega, expelling him back to his own universe of anti-matter. The Time Lord High Council on Gallifrey detects the end of the threat.

Once Tegan has checked on her cousin’s progress in hospital, she decides to rejoin the TARDIS crew - this time as a willing traveler.

Cast
Doctor Peter Davison (Fifth Doctor)
Companions Sarah Sutton (Nyssa)
Janet Fielding (Tegan Jovanka)
Guest stars
Leonard Sachs — President Borusa
Elspet Gray — Chancellor Thalia
Michael Gough — Councillor Hedin
Paul Jerricho — The Castellan
Max Harvey — Cardinal Zorac
Colin Baker — Commander Maxil
Ian Collier — Omega/The Renegade
Neil Daglish — Damon
John D. Collins — Talor
Alastair Cumming — Colin Frazer
Andrew Boxer — Robin Stuart
Maya Woolfe, Guy Groen — Hostel Receptionists
Malcolm Harvey — The Ergon

Production
Writer Johnny Byrne
Director Ron Jones
Script editor Eric Saward
Producer John Nathan-Turner
Executive producer(s) None
Production code 6E
Series Season 20
Length 4 episodes, 25 minutes each
Originally broadcast January 3–January 12, 1983

source: wikipedia