All of Keiji's body piercings symbolize a secret contract, which stipulates that all his needs would be completely taken care of by two twin brothers, Sou and You, in exchange for being their pet. However, the appearance of Miyama—Keiji's first actual friend—starts changing things. For the first time, Keiji finds it difficult to keep this dark secret buried, and the thin balance he tries to maintain unknowingly starts crumbling bit by bit... (Source: MU)