Rika gets into forbidden sexual intercourse with her brother-in-law, Kentaro, while her husband is absent. As the couple's relationship cools down, he entrusts himself while resisting Kentaro's invitation. Rika is disturbed by reason so much that she thinks it is an unforgivable act. A sister-in-law and a brother-in-law who are rubbed with messed up boobs full of charm that they have left over and meet densely from morning till night. The best time to keep seeking each other, a sense of immorality and a sense of euphoria mix violently in the brain.