July 1st, 2030. Manga editor Nishino Mizuho is having the worst 27th birthday ever. The manga she’s in charge of will be ending. However, when she sees a group of high school students having fun, she recalls her own adolescence. 10 years ago, during her second year of high school, Mizuho had four childhood friends who she grew up with in a residential neighborhood known as Koigahama Highlands…