After graduating from university, Akira immediately left his family and moved into the school's dormitory. During this time, his father remarried another woman. He did not resent his stepmother; on the contrary, he was very grateful that she always cared for him and worried about him, helping him forget the feeling of loneliness of living alone. Finally, the day of the graduation ceremony arrived, but Akira's father could not attend due to work commitments. Just when he thought he would have to go through this important day alone, he suddenly saw his stepmother waving and smiling happily from a distance. The two went out to celebrate, and since his stepmother drank a lot, Akira had to take her back to the hotel. Just as he was about to leave, his stepmother held him back, gave him a passionate kiss, and confessed her feelings for him. And from that moment on, their inappropriate love affair began...