The Doctor - William Hartnell
Ian Chesterton - William Russell
Barbara Wright - Jacqueline Hill
Susan Foreman - Carole Ann Ford

Za - Derek Newark
Hur - Alethea Charlton
Old Mother - Eileen Way
Kal - Jeremy Young
Horg - Howard Lang

Designers - Peter Brachacki, Barry Newbery
Costumes - Maureen Heneghan
Make-Up - Elizabeth Blattner
Incidental Music - Norman Kay
Special Effects - Visual Effects Department of the BBC
Fight Arranger - Derek Ware
Film Cameraman - Robert Sleigh
Studio Lighting - Geoff Shaw
Studio Sound - Jack Clayton
Production Assistants - Douglas Camfield, Tony Lightley
Assistant Floor Manager - Catherine Childs

Two school teachers are perturbed by one of their pupils, Susan Foreman. In some cases she is exceptionally bright, sometimes to the point of overshadowing her teachers. But on occasion she has shown a lack of knowledge of the basics, such as the currency that England was using.

Worried by this the two teachers, Ian and Barbara, decide to follow her to her home in order to talk to her grandfather. Instead they see her enter a junkyard. When they follow her inside there is no sign, Although there is a strange, vibrating police telephone box.

They hear Susan inside, and when her grandfather returns they barge past him and into the police box - where they find a large, brightly lit, room with a mushroom shaped console in the centre. The Doctor is not happy at the intrusion, and says that if he lets them go free they will inevitably tell someone about what they saw. Before anyone can stop him the Doctor dematerialises the TARDIS.

It re-materialises around 100,00 B.C. where they have to battle to escape from primitive man. The Doctor attempts to take the teachers back to their own time, but materialises on an unknown world.

Episode One - 'An Unearthly Child'

On a foggy London night, a policeman makes his rounds, passing I.M. Foreman's junkyard at 76 Totter's Lane. In the junkyard stands an incongruous-looking police box emitting an eerie hum.

Another day of classes ends at the Coal Hill School. History teacher Barbara Wright and science teacher Ian Chesterton compare notes on an enigmatic student, Susan Foreman. Her knowledge of history and science surpasses the rest of the class and possibly the teachers. However, she has very curious gaps about present-day culture — she forgets, for example, that England has yet to adopt a decimal currency. Barbara has encouraged her to specialise in history, but Susan is resistant to her suggestion about in-home tutoring, saying her grandfather, with whom she lives, doesn't like strangers. Barbara tells Ian she got Susan's address, 76 Totter's Lane, from the school secretary. She went there and found not a house, but a junkyard. They find Susan so Barbara can lend her a book on the French Revolution. Ian offers Susan a ride, but she declines. Ian and Barbara resolve to follow her home. After they leave the room, Susan reads the history book, and remarks, "That's not right!"

Arriving by car at 76 Totter's Lane, Ian and Barbara see Susan enter the junkyard alone. Following from a distance, they search the junkyard for her in vain. Ian is transfixed by a police box there which hums. Touching it, he exclaims that it's alive. They hear someone coming and hide. An old man approaches the police box and unlocks it. The teachers seem to hear Susan's voice from inside, greeting him. They confront the old man, who brusquely shuts the door and refuses to acknowledge that anyone is inside. When they threaten to go to the police, the old man calmly dismisses their claims. The door opens from the inside. Hearing Susan's voice again, the teachers push past the man. They are astounded to find themselves in a much larger space, with futuristic electronic panels, and a central hexagonal control console. Susan is shocked to find her teachers there. The old man, her grandfather, is furious at their intrusion.

Susan and her grandfather, who calls himself simply the Doctor, say the police box is actually a disguise for their space-time ship, the TARDIS. They are alien refugees from another planet and time. Despite Susan's protests, the Doctor prepares the TARDIS for takeoff, saying he must kidnap Ian and Barbara to protect Susan and himself. The sudden takeoff renders the two schoolteachers unconscious. The TARDIS arrives on a Palaeolithic landscape, over which falls the shadow of a man.

Episode Two - 'The Cave Of Skulls'

The shadow is of a man dressed in animal skins. He watches the TARDIS ominously.

A tribe of cavemen are gathered around one of their members, Za. Za is the son of the tribe's previous leader, who never taught his son the secret of making fire. As Za futilely tries to make fire, a female tribe elder throws scorn on Za's abilities and states that Kal, a stranger from another tribe, would be a far better leader. This frustrates Za. Hur, a young cavewoman, tries to pacify him but also warns him that if he loses his position as the leader of the tribe he will lose her; her father is intent on her bearing children for the leader.

Back at the TARDIS, Ian and Barbara regain consciousness to find the Doctor and Susan puzzling over readings displayed on the TARDIS's main console. The Doctor tells them they have gone back in time. This annoys Ian, who demands concrete proof. The Doctor opens the door, revealing the barren desert. All four go outside. The Doctor professes confusion as to why the TARDIS has retained the shape of a police box. Ian apologises to Susan and Barbara for stubbornly disbelieving the Doctor's story. Susan is also surprised that the TARDIS is still in the shape of a police box. She says it has been an ionic column and a sedan chair in the past. The Doctor is elsewhere, checking the environment for radioactivity, when the caveman who was watching the TARDIS sneaks up on him and attacks him. His three companions hear him shout and run to his rescue. When they get there, all they find is the Doctor's bag, hat and geiger counter smashed. Susan hysterically runs off to look for him. Ian and Barbara soon follow but not before Ian finds the sand is freezing cold.

Horg, Hur's father, tells Za that Kal claims he knew how to make fire in his old tribe. Za angrily responds that Kal's tribe all died out. Kal would have died too if this tribe had not saved him.

Hur again warns him; Kal is bringing in meat and winning favour amongst the tribe. Za says if he has to kill a few people to exert his authority, he will. At this point, Kal, who attacked the Doctor, comes in with the old man's unconscious body. Kal tells the tribe that he saw the Doctor make fire and he should be leader of the tribe now, that the Doctor had immense strength and fighting prowess. Za scorns and mocks Kal, but Horg states that Kal is doing far more for the tribe than Za and if his captive can create fire, Kal should be made leader. Za says the Doctor should be taken to the Cave of Skulls and sacrificed so Orb will return.

At this point the Doctor wakes up. He says he can create fire for the whole tribe without any need for killing, but he soon realises he has lost his matches. When he tells the tribe he will need to go back to the TARDIS before they get fire, Za mocks Kal, saying his promise of "an old man who can make fire" was lies. The tribe turns against Kal. In his frustration, he pulls his knife on the Doctor. Kal is on the verge of killing him when Susan, Barbara and Ian attack the tribe, knocking Kal off the Doctor. The companions are soon overpowered. Kal approaches Barbara. Before he kills her, Za gets in the way and says the four must be taken to the Cave of Skulls and sacrificed as a gift to Orb. The Doctor and his companions are led away. Horg tries to take Hur from Za, but Za insists that with the Doctor's sacrifice, the Orb will return and fire will return also. The tribe will retain Za as leader. Horg seems to accept this.

The four travellers are sealed in the tribe's Cave of Skulls with the bones of many prisoners. The Doctor notices that the skulls have all been split open.

Episode Three - 'The Forest Of Fear'

Still in the Cave of Skulls, Ian, Barbara, and Susan try to escape; however the Doctor seems disconsolate and unhelpful. Ian shouts at him, prompting the Doctor to suggest that they use the bones of the dead to cut the ropes that bind their hands and legs. The group begins to unify.

Back at the main cave, the tribe are all are asleep. The female elder wakes up. She steals Za's knife and heads towards the Cave of Skulls. Unbeknownst to the old woman, Hur has seen her. When she arrives at the Cave of Skulls, she is met by a large stone that blocks the door. However, she seems to know an alternate route.

Inside the Cave of Skulls, the Doctor and the others are trying to free Ian so he can defend them if needed. Susan screams as the elder bursts though a gap in the undergrowth that blocks the cave.

Hur wakes Za and calls him out of the cave to inform him that the elder took his knife and headed out of the cave. They decide she went to the Cave of Skulls. Hur believes the elder is afraid of fire, so she will kill the four to prevent the tribe from learning the secret.

However, the elder is using the knife to free the four, whilst outside Za and Hur try to move the stone. Just as the stone budges, the four escape out the back of the cave. Za, frustrated, throws the elder to the floor. Hur convinces Za that the only way he will retain the tribe's leadership is by capturing the Doctor and harnessing the fire. Za and Hur plunge into the forest in pursuit of the Doctor.

The foursome are lost in the forest, trying to find their way back to the TARDIS. Yet again, Ian and the Doctor fall out as Ian takes the lead. Whilst they argue, Barbara trips and falls. She lands on a dead boar and screams. This alerts Za and Hur. The movement of the undergrowth impels the Doctor and his companions to hide.

When Za and Hur catch up with them, Za is attacked by a wild beast and injured badly. Against the Doctor's wishes, Barbara and Ian try to help Za. The Doctor tries to stop Susan from going, insinuating that he would leave Ian and Barbara behind. Ian and Barbara help Za, to Hur's bemusement. She does not understand the idea of friendship. Hur is openly hostile to Susan, thinking she is trying to steal Za from her. The Doctor is so desperate to leave that he seems to contemplate killing the caveman, but is stopped by Ian. The Doctor reminds his companions that the tribe elder is still with the cavemen. He worries she may wake them and set off in pursuit of the travellers. This prompts Ian to build a makeshift stretcher to carry Za back to the TARDIS to heal him there.

Back at the settlement, Kal has returned to the cave to find it empty. He questions the prostrate elder, who says she set the Doctor and his companions free. Kal kills her. He returns to the tribe to inform them that it was Za that let the Doctor free so he could keep fire to himself. The tribe are sceptical and Kal says the elder will back him up. When Kal returns to the cave to 'discover' the dead elder, he says it must have been Za that killed her. Kal declares himself leader and takes his new tribe off to find Za.

The Doctor and his companions happily find the TARDIS. However, their escape attempt is foiled when they find the tribesmen lying in wait for them.

Episode Four - 'The Firemaker'

The four travellers are returned to the encampment. At first, the tribe is hostile to Za and his friends, especially when they accuse him of killing the tribal elder, but the Doctor convinces the tribe that Kal killed Old Mother by tricking Kal into showing the tribe his bloody knife. The Doctor and Ian lead the tribe in an attack which drives Kal into the forest. The recovered Za is again declared leader, but instead of expressing his gratitude by freeing the travellers as the Doctor expected, he orders them returned to the Cave of Skulls where he will either learn the secret of fire from them or sacrifice them to Orb.

In the Cave of Skulls, Ian makes fire for Za, using friction for a spark, hoping this gift will convince the tribe to set them free. Za comes to speak with them and is entranced by the fire. Ian says that in his "tribe" all members know how to make fire. Za asks Ian if he is the leader of his tribe. He responds (with a nod to Susan) that the Doctor is the leader.

Meanwhile, Kal sneaks back into the camp. He kills the guard outside the cave and attacks Za. Za fights and kills Kal, confirming his leadership. With fire at his disposal, he is now undisputed. However, he still leaves the Doctor and his companions to languish in the cave.

After going out hunting, Za decrees that the travellers will merge with his tribe rather than leave and orders them confined to the Cave indefinitely. The four try to think of a means of escape; absentmindedly, Susan places a skull in a flame. This leads Ian to devise a plan to scare and distract the tribe enough to let them flee. Four skulls are placed on top of burning torches. This ghoulish vision distracts the cave dwellers, allowing the travellers to escape into the forest. This time, the four travellers make it back inside the TARDIS; the Doctor only just makes it in before the tribesmen catch up with them. The TARDIS dematerialises as the tribesmen throw spears at the craft, leaving them staring in amazement.

The Doctor explains that he has no idea where or when they will end up next because the TARDIS is not displaying any data to help him direct the ship. In time, the scanner shows their new destination, a mysterious jungle with strange-looking trees. Before they go out to explore the planet, the Doctor asks Susan to check the radiation levels. They read normal. As the four leave the console room to clean themselves, the radiation detector's needle passes into the "Danger" zone...

[Source: TARDIS Wikia]