ススキノハラの約束 ～幾千の夜をめぐる二人の恋物語～

Main character attends high school and suffers from nightmares every night. The strange thing in the nightmares is that girls there are from the real life around protagonist. Then one day a girl appears before him asking forgiveness for sending him into these dreams, but also asking for his help... [From vndbreview]