Mako, who is married to a man much older than her, has been unable to get along with her stepchild. One day, her son peeks at her relaxing with her husband with a resentful look on his face. Mako, noticing, desperately begs his son to accept her as a member of the family. Secretly harboring lust for Mako's large breasts, Mako takes advantage of her lack of assertiveness and demands that he let him fondle them. Though confused, Mako accepts, wanting to close the gap between them. However, his demands gradually become more extreme...