When Asaka was 18, she became pregnant with her senior at university and gave birth to her child. After that, her senior lost contact with her, and Asaka was left to raise her son, Masaaki, on her own. Masaaki grew up watching his mother work as a nurse and send him to university, and he grew up to be a good, earnest boy. But now his son has graduated from university and is looking for a job. Wanting to spend their remaining time together in peace, Masaaki uses the money he has saved from his part-time job to take Asaka on a trip to a hot spring.