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-

Hoping to find her mother who had been replaced, Shinohara Mifue decides to attend SweetP's tea party, where all kinds of information gathers. However, everyone there is too absorbed in the sweets and none of them will listen to her. Mifue struggles to act dreamy-cute in order to get them to talk, but... Meanwhile, after Ritsu saw the end of their world, he heads to the old school building's music prep room to meet with Shogo.