Since her mother's death, Akio has been studying hard and doing housework. Some time later, his father remarried to Kimiko, an extremely beautiful woman. Kimiko was very interested in Akio, she treated him very well. Being close to a beautiful and charming woman like Kimiko, Akio gradually develops evil thoughts. He decides to take over the beautiful stepmother. Because the medicine is not strong enough, Kimiko regains consciousness while Akio is "acting". Despite Kimiko's weak resistance, Akio is determined to take over her. After regaining consciousness, Akio realized that he had done something unforgivable. He decided to lock himself in his room, which made Kimiko and her husband extremely worried. On the day his father went on a business trip, Akio suddenly left the room and wanted to have sex with his stepmother again. Kimiko agreed, but this would be the last time. And then that last time lasted until later...