Forever-young Oscar, in a present-day prison cell, tells a story from his early life. As Diver, one of the first Homo sapiens , he's the sole survivor of our people when our original home, Lake Makgadikgadi, dries up. Searching in vain for others, desperately lonely, he encounters a stranger with burning eyes, whose uncommon beauty calms Diver's fears. Fiery-eyed Geb is a godlike being allied with animals. At first, he's charged with orchestrating Diver's death. Nothing personal, he likes Diver, but duty comes first. For the moment, Diver is the last of our kind, and Geb is tasked with keeping it that way. Before Diver outwits the prehistoric animals sent to kill him, Geb shows him their lives through the animals' own eyes. When he defeats the animals, Diver regrets their loss. This opens Geb's heart. He works to earn Diver's trust, a difficult task considering their history and Geb's spiritual constraints. Courting Diver, Geb forsakes his duty and makes a big sacrifice to prove his love. Diver learns the secret of how our people might resurface, and Geb promises to always be with him. In his cell, Oscar suffers a flawed romance, gives his blood for experiments, and meets a strange computer program, John Doe, struggling with amnesia. This AI being loves Oscar's story of two ancient enemies becoming lovers and saving humanity. When John remembers his lost identity, he helps Oscar escape.