Gnarrk loses his job at the Forbes Foundation, a social research institution, when his past as a rehabilitated Cro-Magnon man becomes known. Then Gnarrk runs wild, smashing an Aztec Indian tribe, and finally menacing even Lilith, until the sound of her voice brings him back to his senses. Freed by the Aztecs, who now recognize Gnarrk as a superior warrior, the Titans discover that a group of bank bandits have become victims of a poisoned stream, and return their bodies and loot to civilization, while keeping secret the hidden native tribe’s existence.