When Kiyoka was 18 years old, Yuuki was born. Kiyoka raised Yuuki alone. To prevent him from feeling pity, she quit university and worked late into the night, working tirelessly without rest. Thanks to her efforts, Yuuki was able to go to university, but he always felt lonely. When Yuuki turned 20, Kiyoka decided to use her accumulated paid leave and the two of them headed to a hot spring inn. However, Kiyoka was constantly thinking about work.
