The song, "Red," serves as the opening theme for Kagerou Daze: In a Day's and is performed by GOUACHE. On November 3, 2016, IA Project's official YouTube channel released the music video, which promotes the movie's release at the end. While the DVD/BD version of Kagerou Daze: In a Day's includes the song, it lacks the advertisement. The music video features a compilation of the entire franchise, effectively refreshing viewers before the film's premiere the following day.