After seeing her husband off, Sumire indulges in her morning routine of masturbating. Every night when her husband comes home from work late, he finishes dinner and goes to bed right away, so the couple doesn't have any nighttime fun. However, by bad timing, the front door seems to have been left unlocked and her father-in-law, who was passing by, came in. Having been seen masturbating, Sumire has no excuse, and her father-in-law pushes her down, inserts his fingers and tongue into her wet vagina from masturbation, and she climaxes many times with her hips raised. He even takes photos and videos of her wet vagina on his smartphone, and she becomes his obedient slave.