A careless accident by a natural-born sister-in-law; her unsuspecting and impulsive cohabitation with her; Mori Aki KSBJ-432

After returning from a business trip overseas, Shinji stayed at his older brother and sister-in-law's house. His sister-in-law, Aki, was incredibly naive and impulsive! From her underwear being completely exposed to barging into the bathroom, Shinji was constantly aroused by her unconscious allure. One night, a drunk Aki asked him to "rub me a little more," so Shinji engaged in forbidden sex with her right next to his brother! Although she lost her memory the next morning, her body couldn't forget the pleasure, and she began unconsciously launching attacks on him at night!