His mother, who had raised him alone since their divorce several years ago, is hospitalized. Satoshi, his only son, sits in the hospital room staring blankly at his mother's hands, which have become very thin. Satoshi is worried about his future life, and above all, whether he will be able to pay for his mother's medical expenses. Then his aunt Natsuko comes to visit him. Satoshi is Kokoro by Natsuko's words, "It's okay," which she says to him after meeting him for the first time in a long time. And in this situation, the distance between Satoshi and Natsuko begins to grow closer...