Childhood friends Chiaki and Kazuma have been brought up like brothers, but that all shatters when Kazuma catches Chiaki masturbating and, in the heat of the moment, ends up lending a hand. From that night on, the two of them help each other out to satisfy their base urges—that is, until Kazuma gets a girlfriend, and Chiaki realizes his feelings go beyond friends with benefits. Will these childhood friends be able to go back to the way they were before? Or will their relationship manage to bloom into something more?