In the underground arenas of a wasteland metropolis, Ryker, an F-rank underdog, risks his life in brutal bare-knuckle fights to save his sister, Lena, from a fatal genetic disease. Driven to the brink, he swallows an ominous Insect King egg offered by the Black Market King, unleashing a terrifying power within himself. Armed with this monstrous ability, Ryker defies class prejudice and claws his way up the ranks, only to find himself steadily mutating into something inhuman. As the dark truth comes to light, he discovers that his sister's illness and his parents' deaths are tied to a sinister imperial conspiracy disguised as human-insect hybridization. With war and a relentless swarm engulfing the city, can Ryker—on the verge of complete metamorphosis—cling to his fading humanity and save the only family he has left?