Sora no Aosa o Shiru Hito yo

Second-year high school student Aioi Aoi feels indebted to her sister Akane ever since her sister gave up her dream to go to Tokyo with her ex-boyfriend Kanamuro Shinnosuke, a struggling guitarist, in order to take care of her after they lost their parents in an accident 13 years ago. One day Aoi is invited to perform as a session musician at a music festival for a famous enka singer named Nitobe Dankichi. On the same day Shinnosuke returns to their town after being away for a long time, and then a boy named Shinno mysteriously appears who is actually time traveling Shinnosuke from 13 years prior and Aoi falls in love for the first time...