In a world where humans and monsters coexist, humans live in the city of Tokyo, while monsters inhabit the surrounding wilderness. Amidst this complex society, the novel's protagonist, a young man named Gennosuke, is a member of the "Omega Tribe," a group of humans who possess incredible strength and agility due to a mysterious catalyst. With his unique abilities, Gennosuke is part of a special organization that interacts with the monster population, serving as a mediator between the two species. However, his life takes a dramatic turn when a powerful monster is brought to the city, threatening the delicate balance between humans and monsters. As Gennosuke delves deeper into the mystery surrounding this new arrival, he uncovers a shocking truth about the Omega Tribe, himself, and the true nature of the world he lives in.