Yuta returns to his wife's parents' home for the first time in a while and finds himself captivated by his stepmother Yuka's timeless beauty. That evening, with his wife away at a class reunion, Yuta is left alone with Yuka for dinner, feeling tense and uneasy. Trying to ease his nerves, Yuka offers him drinks but ends up getting drunk herself. Overcome by uncontrollable desire, she pins Yuta down and takes him by force. The next morning, still groggy from intoxication, Yuka tries to pretend the incident never happened—but the pleasure she experienced lingers in her mind, impossible to forget, and a new, forbidden desire begins to stir within her.