Ran Matsuno has lived with her father-in-law for three peaceful years, but her sex life is her only frustration. Her premature husband always finishes before she can climax, leaving her unsatisfied every time. Her pent-up desire grows until she finally masturbates while the two men are away. Her father-in-law unexpectedly returns and catches her in the act, beginning a secret arrangement in which he gives her the orgasms and repeated creampies her husband cannot.