Mari informs Dia about plans to close Uranohoshi and merge with another high school due to lack of applicants. When Ruby tells the other about it, Chika decides to follow μ's' example and try to save their school. She decides to make a promotional video to attract applicants, but struggles to find some actual good things to say about their town. As Chika becomes determined to figure out an answer without relying on Mari, she learns that Dia used to love idols, but is stopped from inquiring further by Ruby. Later, as girls from all over town gather to clean up the beach, Riko inspires Chika to get their help in filming their promo video.