The story follows Yū Honda (Takahiro Nishijima), a young teenage Catholic attempting to live his life in a faithful and orderly manner. His father, Tetsu, has become a devout Catholic priest following the death of Yū's mother, and operates his own church. Yū's father asks Yū to Confession (religion) his sins, but Yū believes he is a good person, who has little to confess. At first he makes up sins, but his father sees right through him, and Yū sets out to commit real sins. Because of this, he falls in with a questionable crowd.