Snap is destined to lead the people of Kura, a matriarchal society of Homo erectus, and must choose a mate for her first Bonding Ceremony. When Whistle, Snap’s mother and the next leader of Kura, chooses Bapoto, a stranger who steadily undermines the timeless traditions of Kura, Snap is brutally cast out. Abandoned and on her own to survive or perish, Snap risks her life-and the future of her people-to stand up against an unthinkable evil.