After a whirlwind marriage, Yuka expects a quiet life with her kind husband, only to learn that his withdrawn adult son Taichi will be living with them. One night she catches Taichi using his eerie, treasured sex doll, but her husband offers no help. While cleaning Taichi's room in his absence, she accidentally breaks the doll. When he returns and sees what happened, he attacks his stepmother and forces her to become its replacement.