Riu Nagata has a husband 35 years her senior. The two have enjoyed their quiet life together, but she has never felt satisfied in bed. One day, her husband tells her she may have an affair as long as she continues taking proper care of the house. Conflicted, she lets time pass without acting—until a recent reunion brings her back together with her first love. After sleeping with him once, her dormant desire to cheat is fully awakened.