Shikishima Ritsu was living a fulfilling high school life. Then one day, when Ritsu heard the new song from popular idol, μ, he noticed a cry for help hidding within the song. Ritsu tried to confirm it with his friends, but none of them would respond to his questions, and they even acted off. The suspicious incongruities continued piling up until the new year's entrance ceremonies. Yet the new students entering the school were-

A month has passed since their battle. μ has gone into hiding and the Musicians haven't made any obvious moves either. During that time the former Music Prep Room has become the Go-Home-Club room, and the members of that club share a hot pot. While Ritsu is out shopping everyone around him suddenly disappears and the city transforms into a strange place. There μ appears before him and--

Now, at the end of the fleeting light, there's a glimpse of...