My sister married a rather plain, slightly older-looking man, but after meeting him a few times, I discovered that he was an outrageous pervert. I am secretly just as kinky, so my brother-in-law and I became fuck buddies who can indulge each other's urges. My sister knows nothing about it—and honestly, I wish I had married him instead. Mio is single and proudly perverted. She left her office job and now works part-time. She played table tennis at school and fondly remembers fooling around in a convenience-store back room and at a shrine at night. She enjoys both dominant and submissive roles, admires Yuu Kawakami, dislikes forced deepthroat, loves having her feet licked, and fantasizes about teasing a man until he snaps and overpowers her. Bondage, NTR, groping role-play, and being overpowered after taking control all appeal to her, though her submissive side is stronger. Mio meets her brother-in-law at a love hotel equipped with restraints and a massage-parlor-themed playroom. Their erotic-massage role-play quickly escalates, and he makes her cum repeatedly. She then takes control for revenge, promising that the payback will continue. Finally, a male friend joins them for a creampie threesome—intense, kinky sex between an adult brother-in-law and sister-in-law with no blood relation.