Hibiki, who raised her son alone, saw the shadow of her late husband in her son when he took care of her after she collapsed from overwork. She ended up having a physical relationship with him just once. Three years have passed since then without any issues, and now Hibiki starts to consider remarriage. While hoping for a happy life with her three-person family, she also feels guilty about the mistake made three years ago. To sort out her feelings, Hibiki decides to go on a hot spring trip with her son.
