A five-year-old girl, Ayla, who readers come to understand is Cro-Magnon, is orphaned and left homeless by an earthquake that destroys her family's camp.

Creb is the group's "Mog-ur" or shaman, despite being deformed as a result of a difficult birth caused by his abnormally large head, and the later loss of an arm and eye after being attacked by a cave bear.

The Clan worships spiritual representations of Earthly animals, called totems, that they believe can influence their lives by sending good or bad luck, and for whom Mog-ur acts as an intermediary.

Brun allows Iza to treat the dying child and agrees to adopt her providing Creb can discover her personal totem spirit.

He cites the cave lion attack the girl experienced shortly before being discovered as proof that its spirit marked her so that she could be adopted into the Clan.

When they are young adults, he brutally rapes Ayla in a bid to demonstrate his total control over her, and he continues to sexually assault her multiple times a day.

Having dreamed of being a mother for most of her life and convinced that this may be her only chance due to her powerful totem, Ayla refuses Iza's suggestion that she take medicine to abort the child.

Iza becomes extremely unwell due to her chronic illness and at her deathbed, she was just past twenty-six with white hair, gaunt frame and wrinkled skin.

The sequel, The Valley of Horses, continues Ayla's story, which is further developed in the four other books of the Earth's Children series: The Mammoth Hunters, The Plains of Passage, The Shelters of Stone, and The Land of Painted Caves.

[2] Some of the descriptions are based on the first adult Neanderthal skeletons found in Iraq from the cave burial at Shanidar, dating between 60–80,000 years BP.