Rainbow Song is a beautiful, yet tragic love story about a romance that never happened. Two young film students, Tomoya and Aoi, become fast friends after being put on a project together. Quickly, Tomoya becomes enamoured with the young girl but is too afraid to tell her his true feelings. After graduation, Tomoya continues living in Japan working on a film set and Aoi leaves to work in America. The movie takes a turn as Tomoya finds out that Aoi never made it to her destination because of a plane crash. He then starts to become consumed with his thoughts, day-dreaming about the love affair that never was nor can be.