After falling asleep in a park, fourteen-year old Zan awakens to find herself transported back in time to the forest world of a band of prehistoric cave dwellers. Adopted by the group, she learns their language and customs, exults in their triumphs, and shares in their grief. However, the society’s wise woman has her doubts about Zan, who she believes has brought misfortune with her. In mortal danger, Zane is able to return to her own time—an eleven-month absence which was only a few hours back home.