Izumi-Kun and his friends are getting ready for the school's cultural festival; Izumi-Kun is working with the group in charge of making costumes; Kamiya-San is on duty in the library the next morning with Izumi-Kun, but she's acting differently.
The naturally unlucky Izumi-kun faces another day of disaster; even on his way to meet up with his girlfriend Shikimori-san in the morning, he runs into so many troubles that he's a mess by the time he sees her.
Izumi-kun and Shikimori-san make plans to see a fireworks show together; on the day of the fireworks show, Izumi-kun sees Shikimori-san looking adorable in her yukata and tries his hardest to impress her, but his heroics are no match for hers.