Kota lost his father in an accident at a young age and has lived alone with Rinka ever since. Rinka has loved Kota not just as a mother but with a deep, profound affection that goes beyond a simple parent-child relationship. As time passed, Kota graduated from university and secured a job. However, when he was assigned to a position in the Kansai region, Rinka felt a sharp pain in her heart. She realized that soon she would have to part ways with Kota. One day, Rinka suddenly invited Kota on a hot spring trip. Wanting to make their final moments together before his independence into something truly special, she hoped to create an unforgettable memory between them.