Middle-aged man Matsuo, living in isolation, comes up with an abnormal plan one day—to kidnap and confine a schoolgirl. His target is Sayomi (Rubi Aiba), a pure-looking black-haired beauty. He locks her inside his room, determined to spend lewd, intimate time in their private world. Gradually, a strange bond forms between Sayomi and Matsuo, evolving into a mutually dependent relationship. The story portrays the intertwining of anxiety, desire, and loneliness that unfolds between them.