In a world where werewolves are not a game but a terrifying reality, these monsters devour humans, stealing their appearance and memories to seamlessly replace them. They infiltrate society, living undetected while feeding on others to extend their own existence. Someone you trusted yesterday could be an impostor today. This is the unsettling truth that collides with the life of Hironari Haido, a first-year high school student with an abnormally strong will to live.

Hironari is an ordinary teenager who loves watercress, enjoys morning jogs, and is hopelessly bad at the werewolf game that his class plays—he gets flustered just imagining death. Yet his real life is good: he has a cool childhood friend and confidant, Kouki Miyajo, and he has managed to win the heart of the girl he fell in love with at first sight, Hana Nonooka. Their peaceful high school days seem perfect, until the night Hironari encounters a real werewolf. That encounter changes everything: Hironari himself becomes a werewolf.

Transformed into the very monster he feared, Hironari is desperate to hold onto his humanity. He tries to keep his relationship with Hana intact, but during a summer date at an amusement park, a powerful werewolf known as Rust Color approaches him, and Hana begins to sense that something is wrong—“you’ve become a different person,” she says. Meanwhile, Kouki turns out to be a werewolf hunter. Hironari must prove to his oldest friend that he is still himself, even as he struggles with his new predatory instincts and the constant threat of losing everyone he loves.

As the story unfolds, Hironari battles other werewolves, including the Fighting King, a high-ranking monster with a special role. After defeating him, Hironari is recruited by a mysterious red-hooded girl named Blanchett, and he decides to fight alongside the werewolf hunters. Together they infiltrate a massive gathering of werewolves, aiming to earn the trust of the monsters and gather intelligence in order to reach the boss who rules over them. The narrative weaves through intense action, psychological suspense, and Hironari’s unyielding desire to survive without sacrificing the bonds that make him human.

The manga follows Hironari’s journey from a frightened teenager to a determined fighter walking a knife-edge between two worlds. His core motivation—the relentless drive to stay alive—shapes every decision, whether he is confronting enemy werewolves or trying to protect the people who still believe in him. Over the course of the story, he forges uneasy alliances, faces brutal enemies, and must decide how much of his own soul he is willing to lose in order to keep living.