Kouta, worried about Mai's health, walks her to and from school every day. One day, they find an abandoned kitten, and secretly keep it at a shrine. At first, Kouta considers it bothersome, but when Mai calls him the kitten's "father", Kouta begins to feel a sense of responsibility toward it.

However, recently Kouta has been drifting apart from his male friends with whom he used to play so often. When they invite him out to play, he finds himself unable to refuse, leaving Mai to take care of the kitten by herself...