Mio is 42 years old. At a reunion of her alma mater, which she attended for a break, she falls into an affair with Ichijou. Knowing it's wrong, the sense of transgression of being held by a man other than her husband turns into a pleasure, and Mio falls into the spiral of the affair. As they continue to meet, Mio's reason becomes unstoppable, and she even offers her anus, which her husband has never entered, to Ichijou. "You forgive me... I can't go back..." The drama of a married woman drowning in desire―.