Takao Kasuga, a high schooler deeply fascinated by poetry, holds Charles Baudelaire in high regard, adorning his room with the poet's portrait. One day, Takao forgets his copy of Baudelaire's The Flowers of Evil in the classroom. When he goes back for it, he takes the athletic clothing of Nanako Saeki, whom he calls his muse and sees as a femme fatale. Despite his horrible act, which he considers a sin while others perceive as a crime, Takao is horrified to learn that Sawa Nakamura, his classmate and social outcast, knows about his theft. Blackmailed by her, Takao must engage in Sawa's disturbing fantasies, or face the consequences of his actions being revealed to everyone. Now trapped in an increasingly troublesome cycle of events, will Takao ever manage to untangle himself from Sawa's hold and make amends for his wrongdoing?