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. She wanders naked and unable to feed herself, for several days. She is attacked and nearly killed by a
cave lion, and, suffering from starvation, exhaustion, and infection of her wounds, she collapses, on the verge of death. The narrative switches to a group of people who call themselves "Clan" and who the reader comes to understand are
Neanderthal. Their cave was destroyed in the earthquake, and they are searching for a new home. The
medicine woman of the group, Iza, discovers Ayla and asks permission from her brother Brun, the Clan leader, to help her, despite the child being clearly a member of "the Others," the distrusted antagonists of the Clan. The child is adopted by Iza and her eldest brother Creb. 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. Through
meditation, Creb comes to believe that the child may be protected by the spirit of the cave lion, a powerful totem never given to a woman and only to very few men. 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. The girl travels with them for a while and starts to heal. When the group stops to discuss what they should do since they have not found a new home, Ayla wanders and discovers a huge, beautiful cave, perfect for their needs. Many of the people begin to regard Ayla as lucky, especially since good fortune continues to come their way as she lives among them. In Auel's books, Neanderthals possess only limited vocal apparatus and rarely speak; however, they have a highly developed
sign language. They do not laugh or even smile, and they do not cry; when Ayla weeps, Iza thinks she has an eye disease. They also mature very early - to the point a person in their 20s and 30s is considered old and they become pubescent at around 7–9 years old with few maturing at 10 years old. Very soon after, they are given a mate and have children. Iza was considered to have a
geriatic pregnancy when she was nearly twenty and had stumbled upon Ayla. Ayla's different thought processes lead her to break important Clan customs, particularly the
taboo against females handling weapons. She is self-willed and spirited, but she tries to fit in with the Neanderthals, although she has to learn everything first-hand; she does not possess the
ancestral memories of the Clan that enable them to do certain tasks after being shown only once. Iza is concerned that when Ayla grows up, nobody will want her as their mate as she is very ugly to the Neaderthal, making her a burden to the group. She therefore trains Ayla as a medicine woman of her line, the most prestigious line of medicine women of the entire Clan. This will give Ayla her own status, independent of whether or not she is mated. It takes Iza much longer to train Ayla than it will her own daughter, Uba, since Ayla does not possess the memories of the Clan. Ayla's main antagonist in the novel is Broud, son of the leader Brun, who feels that she takes credit and attention away from him. As the two mature, the hatred in Broud's heart festers. When they are young adults, he brutally rapes Ayla in a bid to demonstrate his total control over her; he continues to sexually assault her multiple times a day. She sinks into depression that leaves her despondent and uninterested, and she becomes pregnant soon after at the age of approximately 11 years old. Iza explains to Ayla that her unattractive appearance compared to a Clan woman will likely preclude her from obtaining a mate before she gives birth — a circumstance Iza's people believe will bring the group bad luck. 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. Following a difficult pregnancy and a near-fatal labor, Ayla rejoices in the birth of her son Durc, but because he has a number of Cro-Magnon features, he is classified by the Clan as deformed and is almost taken away from her, but after much pleading and convincing, Ayla is allowed to stay in the Clan and keep her son Durc. Iza becomes extremely unwell due to her chronic illness; at her deathbed, she was just past 26 with white hair, gaunt frame and wrinkled skin. The book ends with Broud's succession of Brun to leadership and Goov's succession of Creb as mog-ur. Broud orders Goov to place an immediate death-curse on Ayla. Another earthquake then happens, killing Creb. Ayla sets off to find other people of her own kind. Durc remains with the tribe under the protection of Brun who admonishes Broud and regrets his decision to make him leader. ==Sequels==