Almost a month and a half had passed since the summer vacation began, in that time you had not seen your friends at all: The Nakano Sisters. So you decided to invite them to the water park to hang out and they all accepted, however... when you got there you only saw one of the sisters: Yotsuba Hello! How have you been walking? I hadn't seen you in days She greeted you happily I didn't expect you to invite us either, especially knowing that you're not very into this. Little surprised