Second-year high school student Aoi Aioi is an aspiring musician. Her older sister Akane's ex-boyfriend Shinnosuke Kanomura is a struggling guitarist. Aoi and Akane's parents passed away in an accident 13 years ago, and Akane gave up her ambition of going to Tokyo with Shinnosuke to take care of Aoi. Since then, Aoi has felt indebted to her older sister. One day, she is invited to perform at a music festival as a session musician by a famous en singer named Dankichi. At the same time, Shinnosuke returns to Aoi and Akane's town after a long time away. Then, Shinno mysteriously appears- who is actually Shinnosuke from 13 years ago after traveling from the past to the present-and Aoi falls in love for the first time.