This role-play is performed by adults. Yusei is at a loss when his wife leaves him after a fierce marital quarrel. Unable to see Yusei in such a state, his wife's sister Serino decides to act as a mediator. It would be reassuring if Serino, who is beautiful and caring, would cooperate. As Yusei rejoices at having found a reliable ally, Serino keeps an eye on Yusei, hoping to calm him down. Eventually, Yusei, who seems completely exposed, invites her to take a bath, and at the same time, Serino also takes off her clothes...