Wakana Gojo is a high school student who dreams of becoming a kashirashi for hina dolls one day. Because his life is all about making hina dolls, he has a hard time fitting into his class because his interests are so different than anyone else’s. His classmate, Marin Kitagawa, is always at the center of attention and from another world. One day, they both end up on classroom cleaning duty and…

Summer vacation is coming to a close. Wakana received an SOS from Marin, who hadn't finished her homework, so he ended up helping her study at her house. They later realize that Marin had forgotten some math drills at school, so they go to get them. While alone at the school, Marin and Wakana make plans to go to a summer festival together. And when that day finally arrived...