Yuki's mother, Chisato, is a single mother who got divorced 15 years ago. Chisato worked hard to raise her Yuki well, and she graduated from college and she grew into a fine member of society. Yuki gifted her hot spring trip to her Chisato with her first paycheck. Chisato was really happy that her Yuki invited her on her trip, but she also felt a little lonely as her role as her mother seemed to have come to an end...
