At age 20, Miki became pregnant through an affair and gave birth to Tatsuya, beginning her life as a single mother. Concerned for Tatsuya's future, she continued working hard as a career woman, her determined yet pitiful struggle evident in her daily life. Working late into the night and rarely having time off, Tatsuya's loneliness grew deeper each day. Her boss suggested she use her paid vacation to take a trip with her son and experience the outside world together. Grasping at this small hope, Miki decided to head to a hot spring inn with Tatsuya. Yet, her mind remained consumed by work.