At the time the tribe was undergoing a crisis as the previous leader had been killed before he was able to pass on the secret of making fire to his son Za. As a result, Za's leadership of the tribe was in question, and Kal hoped to take advantage of the situation.
Kal saw his chance when he observed a group of strangers emerge from a strange "tree", and later witnessed the group's leader, an old man, produce fire by striking a tiny stick on a rock and proceed to breathe smoke. Kal captured the old man and took him to the tribe where he hoped to force the stranger to tell him the secret.
Za's mother was convinced the use of fire had brought divine wrath down on her husband, and feared the same would happen to the entire tribe if the old man and his friends were allowed to produce the secret. As the tribe slept, she snuck into the cave where the strangers were held and helped them to escape into the forest. After Za and his mate Hur left in pursuit of the strangers, Kal in anger killed the old woman. When the strangers later returned with Hur and an injured Za, the old man was able to prove that it was Kal who killed Old Mother, and the tribe in anger drove Kal into the darkness.
Kal snuck back, seeking revenge on the strangers. He was confronted by Za, who killed Kal in a fight. Za then proceeded to use the secret of fire taught him by the strangers to re-establish his leadership over the tribe.