Aoi Miura (Sota Fukushi) was born and grew up in Toyama Prefecture. He has an indecisive personality and does not like summer. He was the focal member of the high school swimming team, but he now works as an assistant at a small architectural office in Tokyo.

One summer day, he meets his childhood friend and first love Akari Serizawa. During their school days they spent everyday hanging out together until the fireworks night in their 3rd year of high school. That night, Akari suddenly disappeared. Now, Akari has a man named Aoi.