Natsumi lives with her daughter and stepson while her husband is away on a work assignment. One morning, she accidentally discovers her stepson masturbating in his room. Moved by compassion, she gently helps him reach climax orally. Witnessing this act excites her daughter, who invites her boyfriend into her room and engages in intense intercourse. Seeing this, Natsumi heads to the shower room to satisfy her own desires but can't resist and ends up going straight to her stepson's room.