A transfer student named Hebigami has a peculiar condition: whenever the temperature drops, his body transforms into a giant snake. He is a descendant of the legendary yokai Yamata-no-Orochi, and his mysterious aura makes most classmates keep their distance. Only Haruna, the girl who sits next to him, sees past his forbidding exterior to his gentle and kind nature. Because his body temperature drops so easily, he cannot revert to human form without external warmth. Haruna begins to take care of him, gradually warming him with her presence and attention. What starts as simple concern slowly develops into a sweet, awkward romance as Haruna finds herself flustered by his innocent physical closeness and his gentle Kansai dialect, while Hebigami struggles to understand his own feelings. The story is set in a contemporary high school, where everyday school life is punctuated by his sudden transformations and the quiet intimacy of Haruna warming him up. As their bond deepens, a new classmate, Ookuma, enters the scene. Ookuma has his own supernatural quirk: he turns into a bear when he becomes sleepy. His cheerful interference adds a playful love-triangle tension, forcing Haruna to confront the difference between liking someone as a friend and liking someone as a romantic partner. The narrative weaves together lighthearted comedy, gentle relationship growth, and the daily challenges of navigating high school while hiding a supernatural secret.