After dusk by the riverside, the quiet high school girl Mahiru spots a strikingly beautiful boy. The next day she discovers he is her new classmate, Sio Magami. Sio appears aloof and mysterious, yet he shows an unexpected interest in the ordinarily invisible Mahiru. She soon learns the reason: Sio is a werewolf, a person who transforms into a wolf when exposed to certain triggers. Mahiru, to his surprise, has a scent that irresistibly draws him out, causing him to shift involuntarily whenever they grow close.

As the two navigate their budding friendship, Sio struggles to control his animal instincts while Mahiru grows more attached to the gentle boy behind the fangs. The story explores their tentative bond and the everyday complications of a human and a werewolf coexisting in a modern school setting. Sio’s family secret runs deeper than his lycanthropy: his mother Anri carries her own hidden intentions regarding the curse that afflicts her son.

A turning point arrives during a festival night, when Sio is overwhelmed by his wolf nature and attacks Mahiru. Horrified by what he has done, he tries to push her away and break off their relationship. Mahiru, steadfast in her feelings, refuses to abandon him and attempts to reach the human part of him. Meanwhile, Anri begins to act on a plan to free Sio from the curse, forcing all of them to confront what it truly means for a wolf boy and a human girl to build a life together. The series is a warm, sometimes sharp-edged story of cross‑species friendship, identity, and the lengths one will go to protect someone dear.