Satoru and Kousei are childhood friends who started living in neighbouring rooms after starting university. Kousei has always been looking after the sickly Satoru ever since that time the latter got injured when they were kids.

One day, the two of them went to a fireworks festival with friends from their university club but Satoru started feeling unwell halfway through. After noticing Satoru's condition, Kousei was about to go back home with him when a club member questioned why Kousei had to go back too. No longer able to stand the strange mood in the club, Satoru came to feel that he is holding Kousei back and getting in his way and thus decided to distant himself from the latter...