Nukui Kyou is a high school student who tends to skip school due to a trauma in his past. Kyou secretly creates songs using vocal song synthesis software as his hobby. Three girls who just entered fifth grade - the crybaby Gotou Jun, the strong-willed Momijidani Nozomi, and the somewhat sleepy Kaneshiro Sora who takes life at her own pace - email Kyou. These three girls, who were raised together like sisters since childhood, want Kyou to help them break into music in this loli & pop symphony story.