After divorcing her husband, Tazuko raised Yuki single-handedly. Determined not to make him feel pitiful, she worked tirelessly and continued to do so even after Yuki started university to pay for his tuition. As the time for Yuki to find a job approached, Tazuko felt a sense of emptiness as child-rearing came to an end. It was then that Yuki invited her on a hot spring trip, and they set off on a graduation trip just the two of them.
