Aoi marries a man who has been divorced before, and ends up living with him, his father, and his son—four people under one roof. Her husband, obsessed with pursuing pleasure, begins tying her up during sex and gradually involves his father and son in intimate acts, turning their household into a place where all three men indulge in Aoi's massive breasts. Through repeated bondage and humiliation, Aoi's latent masochistic desires are awakened, causing her to accept the three men's advances with growing arousal. As family boundaries blur, their relationships transform, giving rise to a twisted new sense of unity.