Khipa Shulgin is a reindeer herder and wildlife guide living with his brothers on an island in the Kamchatka Peninsula. Khipa has inherited a life-threatening heart ailment and travels to the mainland village of Ossora for medical help. After a physical examination, the doctor orders genetic testing and refers Khipa to a cardiologist in Vladivostok. While waiting for his travel arrangements to be finalized, Khipa discovers a poacher's cache and gathers a bear paw as evidence. In Vladivostok, Khipa delivers the paw to a geneticist who uses DNA to convict wildlife criminals. Khipa also connects with an undercover cop who chases poachers, and the bear paw becomes key evidence in breaking up a poaching ring.

As Khipa undergoes medical treatment, archaeologists working at a dig site on his island uncover stone tools made by Neanderthals, and speculation arises that Khipa and his brothers are living Neanderthals. Khipa asks the geneticist to examine his DNA profile to quash these rumours, hoping to prove he's a modern human and preserve his traditional lifestyle. Instead, Khipa learns he is 85% Neanderthal. To further complicate matters, the government collects DNA from his brothers, and a global storm of interest is unleashed.

As he comes to terms with his genetic lineage and with a life-saving device in his chest, Khipa takes on a legal battle to save his island, and his people, from developers and speculators. In so doing, Khipa uncovers dark secrets from Kamchatka's past and the sordid world of wildlife trafficking. Above all, he learns to survive as a Neanderthal in the modern world.

The narrative transports the reader back in time—to the Neanderthal era. Onar and his clan meet a strange and hostile human, Homo sapiens, but fail to build friendly relations. Kidnappings, thievery, and violence break out, and the Neanderthals struggle to defend their homes and territories. When game becomes scarce and starvation threatens their survival, Onar's descendants abandon their homeland and disappear into the mist to become one of earth's "uncontacted peoples"—until the modern world discovers Neanderthals are still alive.