Ever since she got married, Mizuna has been plagued by the insidious sexual harassment of her father-in-law, who lives with her. She has endured it, believing that if she could have a child, her father-in-law's foolish behavior would stop... but she has no sex with her husband and has never been blessed with children. Mizuna's sexual frustration grows day by day, and at the same time, her father-in-law's sexual harassment gradually escalates... And finally, even though she knows it's wrong, Mizuna's unsatisfied body accepts the dark desires of an old man...