In the first episode, "An Unearthly Child", the four main characters are introduced, the Doctor is given vague background information, and the first recorded instance of the TARDIS traveling through time airs. In "The Cave of Skulls", the group encounters a Paleolithic tribe and are subsequently imprisoned by them in a large cave. In "The Forest of Fear", they are shown to escape from the settlement but are subsequently intercepted before reaching the TARDIS. The final episode, "The Firemaker", has the group mediating separate factions of the tribe before fleeing successfully to the TARDIS, leaving Earth and landing on the planet Skaro, leading in to the next serial.
The first episode starts in a junk yard in contemporary London and introduces the four characters who were to form the core of the first year's production. Schoolteachers Ian Chesterton and Barbara Wright are concerned about one of their pupils, Susan Foreman, who seems to have a very alien outlook on England. She is precocious but seems to have strange gaps in her understanding of the world. They have come to her listed address to investigate.
The programme's main prop, the TARDIS, is disguised as a police box, is also introduced, when the teachers hear Susan's voice apparently coming from inside the box. At the time such boxes were a fairly common sight on the streets of London, but only police officers held a key to open them. The TARDIS proves to be no ordinary police box; when Ian and Barbara enter they discover it to be much bigger on the inside than the outside, and furnished with futuristic-looking controls. The time machine retains its outward appearance when it travels through time, which Susan explains as a malfunction in the circuitry that is supposed to adapt its appearance to its surroundings. Susan lives with her grandfather, the mysterious Doctor, who does not otherwise identify himself. He is a cranky, hostile, suspicious old man who appears to be a fugitive.
Fearing that Barbara and Ian will give away the secret of the TARDIS and make life impossible for him in London, he takes the machine to the Stone Age, where the four become involved in a brutal power struggle within a Stone Age tribe. They barely escape with their lives by exploitation of Ian's knowledge of how to produce fire, which induces fear and respect in the primitive Stone Age society. They escape back to their time machine and the Doctor again activates the controls. They travel seemingly at random to a new destination, even the Doctor does not know where. The TARDIS's view screen shows a mysterious scene, a petrified forest, which acts as a teaser for the next story. As the time travellers leave their machine, a radiation meter is shown on the console of the machine, unheeded by them, registering "Danger".
The programme uses the convention that everybody speaks the same language so that the Londoners are easily able to communicate with Stone Age people. In later stories, this convention is explained within the story as a translation function performed by the TARDIS.
Doctor William Hartnell (First Doctor)
Companions Carole Ann Ford (Susan Foreman)
Jacqueline Hill (Barbara Wright)
William Russell (Ian Chesterton)
Derek Newark — Za
Alethea Charlton — Hur
Eileen Way — Old Mother
Jeremy Young — Kal
Howard Lang — Horg
Writer Anthony Coburn
C. E. Webber (episode 1, uncredited)
Director Waris Hussein
Douglas Camfield (film inserts, uncredited)
Script editor David Whitaker
Producer Verity Lambert
Mervyn Pinfield (associate producer)
Executive producer(s) None
Production code A
Series Season 1
Length 4 episodes, 25 minutes each
Originally broadcast 23 November—14 December 1963