Saki inherited her parents’ house and lives there happily with her office-worker husband, quietly supporting him as a childless couple. One summer day, a stranger suddenly breaks in while she is doing housework. Terrified, she soon recognizes him as Kyosuke, her husband’s younger brother. Fired from his job, drowning in debt, and desperate after a year on the run from loan sharks, he forces himself on Saki and then refuses to leave. The worthless brother-in-law who fled back to the family home has become a sex-crazed monster, repeatedly assaulting his brother’s wife without caring whether her husband discovers them.