After graduating from university, Akira left his family and moved to the school dormitory. During this time, his father also remarried another woman. He did not hate this stepmother, he was even extremely grateful for her care and concern for him, helping him forget the loneliness of living alone. Finally, the day of the graduation ceremony arrived, but Akira's father could not come because he was busy with work. Just when he thought he would have to spend the important day of his life alone, suddenly in the distance, his stepmother was waving and smiling happily. The two went to celebrate, the stepmother drank a lot of alcohol so Akira had to take her back to the hotel. As he was about to leave, his mother stopped him, gave him a passionate kiss and confessed her feelings for him. And their illicit love affair began from that moment on.