Since his mother passed away, Akio has been diligently studying and doing household chores. Some time later, his father remarried Kimiko, an extremely beautiful woman. Kimiko cares a lot about Akio and treats him very well. Being close to a beautiful and seductive woman like Kimiko, Akio starts to have evil thoughts. He decides to drug and take advantage of his beautiful stepmother. However, the drug is not strong enough, and Kimiko wakes up in the middle of Akio's attempt. Ignoring Kimiko's feeble resistance, Akio is determined to possess her. After coming to his senses, Akio realizes the unforgivable act he has committed. He decides to lock himself in his room, making Kimiko and his father extremely worried. One day when his father is on a business trip, Akio suddenly leaves his room wanting to have sex with his stepmother again. Kimiko agrees, but this will be the last time. And that last time extends into the future...