俺の幼馴染はメインヒロインらしい。 (Associated Names)

One summer day. Saito Minazuki, who was six years old at the time, happened to find a beautiful girl named Machigane Riri in the mountains and saved her from falling into a waterfall. Since then, the two became childhood friends and often played together, even though their homes were quite far apart. They went to…