Lately, Shirasaka, a high school student, has become anxious and restless. The reason being: his close friend Kuroda, who is better than him in school and in sports, suddenly grew in height, making him look more mature - and he feels as though he will be left behind. One day, after school, when club activities ended, Shirasaka, who still has feelings of anxiousness, was suddenly kissed by Kuroda while napping...!?