HELLO WORLD if: Kadenokouji Misuzu wa Sekai de Saisho no Shitsuren wo Suru

A quiet and unremarkable child, Mirei meets her future self, Misuzu during her middle school life one day. She had come from the future to tell Mirei about the two very important person whom she would meet from now, and to request for her help for a certain task. Through her meeting with Misuzu, Mirei gradually turns from her docile self to an attractive and expressive girl. When she eventually progresses to highschool, she meets the fated two, Naomi and Ruri. For the sake of the happiness of those two, what is it that Mirei can do—. Source: Shueisha