The Hojo and Shizuka families are close neighbors in the same apartment building. They casually agree to swap mothers for one week during spring break, believing their long friendship makes the arrangement safe. Maki and her adult son Kento soon discover that Shizuka's household is troubled: the mother has abandoned her domestic responsibilities, while her adult son Takuro is starved for affection. Before Maki can process the truth, Takuro overwhelms her with his demand for sexual affection in this adult family role-play.