Inheriting her parents' house and living alone without children, Saki lives happily while humbly supporting her office worker husband. One summer day, while doing housework, suddenly a stranger broke in and robbed her. Although extremely scared, Saki recognized that man as Kyosuke, her husband's younger brother. Unlucky in debt, got fired from the company. Saki was forced by her desperate brother-in-law. And just stay home. The scummy brother-in-law who ran back to his parents' house is a sexual monster.

SSIS-602 I secretly feel sorry for my sister-in-law