Kohaku Samejima works as a resident doctor at Usagi Children's Hospital. He aspired to become a pediatrician because he wanted to make children smile, but the children's hospital is full of crying faces everywhere. Naturally, the hospital prioritizes the future smiles of children who will be cured, not the present while they are undergoing treatment. Samejima, who still cannot give up on the "smiles of today" of children in such a field, meets Shio Tokita, a child life specialist (CLS) who specializes in the care of children's mental health. (Source: Comic Zenon, translated)