Uesaka Kazuhi and his family usually visit their grandfather in the summer and when he was small, he once visited the shrine next to his grandfather's house. There, he met a pair of mysterious twins and since then, he's gone to the shrine multiple times in hopes of meeting them again but they never did.

Six years later, Kazuhi visited the shrine again for the first time in a while and there he once again met the twins who were loitering around just like they did back then.

The two seem to not have changed at all since they were kids as Haruka still has her beaming smile and Ryou is still as mature as usual but...!