A daughter couple came back to Eriko who lost her husband and spent a lonely life alone. Eriko felt the joy of being her parent in her lively home after a long absence. Tatsuya, who was nervous about her beautiful mother-in-law, wakes up at night without falling asleep, and sees Eriko's naked body burning after bathing through the gap in the slightly opened door. The next morning, Tatsuya, who can't get away from the scene as it is burned into his mind, attacks Eriko while she is cleaning. The distance between the two who have crossed the forbidden line rapidly shrinks...
