Tribe of Gum The Tribe of Gum was a tribe of Caucasian , cave - dwelling human s that lived on Earth in 100 , 000 BC . They worshipped a sun god called Orb . They were visited by the First Doctor , Susan Foreman , Barbara Wright and Ian Chesterton , who taught them to make fire and to show compassion to one and other . The four fled from them in fear from the tribe and dematerialised in the TARDIS . An alien race known as the Promethean s saw this brief encounter , and decided to continue what they had seen as an abandoned social experiment by giving the tribe psychic metal , which granted them god - like powers and allowed them to travel to the stars in search of more metal , as well as the teachers which had left them before . History . One of the tribe ' s favoured policies was that leadership was given to the one who was able to make fire . Therefore this ability was a closely guarded secret , and passed only from father to son . However , the last firemaker was killed in a hunting accident before he taught the secret of firemaking to his son Za . Therefore the tribe was freezing during the winter and unable to cook their food , which included tiger and bear . Some of the tribal elders however shunned fire altogether , with one woman stating , " There were leaders before there was fire ; fire will kill us all in the end . " Another member of the tribe was an elder named Horg . He was once a great leader , before he got too old . Due to his high status , his daughter Hur was the most prized female in the tribe , and would be given only to the tribe leader . The prospect of Horg ' s daughter made the position of leadership all the more attractive . Za wanted to take what he saw as his rightful place as the leader of Gum , but without the ability to make fire , the others would not wholeheartedly follow him . There was an outsider called Kal who had been taken in by the tribe some time ago . He was full of vigour , and some of the people thought he had a better chance of making fire than Za , and so wanted to follow him . Naturally , a struggle for power broke out between Za and Kal . One day during this power struggle , Kal was out roaming the countryside and came across the First Doctor , who produced fire with match es . He seized this opportunity to knock the Doctor unconscious and haul him back to the tribal caves . Meanwhile , the Doctor ' s companion s Susan , Barbara and Ian had realised he was missing and were out searching for him . But they too were captured by the tribe and brought to the same cave . The Doctor woke up and offered to make fire for the tribe if they took him back to the TARDIS , where he had left spare matches , but the tribe were so involved in their power struggle that they were unable to listen . During an argument , some of the tribe were going to kill the companions on the spot , but Za prevented this , proclaiming that Orb would wish to see them . He believed that if they waited to sacrifice the quartet when Orb next appeared in the sky , then Orb would grant them fire . Thus the prisoners were taken to await their fate in the Cave of Skulls . An elder woman , fearing fire , set the captives free in the night . Za and Hur followed them into the Forest of Fear in order to get their secrets of fire . Za was attacked by a beast . The companions nursed him back to health , and the pair were puzzled at this caring behaviour , as killing rivals was the norm in those primitive times . Meanwhile Kal killed the old woman and blamed Za . Led by Kal , the tribe caught up with the delayed travellers . Kal confronted Za , but the Doctor was instrumental in turning the tribe against Kal by tricking him into showing his blood - stained knife , and they drove him away . The tribe , now led by Za , recaptured the companions and took them back to the Cave of Skulls . Za took this opportunity to learn the fire secrets from them . In the midst of this Kal returned , killed the guard at the Cave of Skulls , snuck in and challenged Za . They fought to the death with Za emerging as victor . With Kal dead , and the knowledge of fire in his possession , Za emerged from the cave as the undisputed leader of Gum . Za insisted on a union between Gum and the new tribe of the companions , and would not hear otherwise . The companions thus used their cunning to frighten the tribe and escape back to the TARDIS . The tribe pursued the companion s , just in time to see the TARDIS vanish . ( TV : " An Unearthly Child " )