Honoka is a girl who loves her school, Otonokizaka Academy. When the school is planned to be closed down due to a lack of applicants, Honoka becomes determined to save it. Learning that school idols are popular, Honoka and her friends start up a school idol group called "Muse" in order to attract new students. Once they successfully prevent Otonokizaka Academy from closing, the girls from "Muse" aim for higher grounds and participate in "Love Live", the ultimate school idol competition. Despite winning the competition, the girls from "Muse" disband soon after for their own personal reasons. Love Live Sunshine! is set in another school, the ocean-side Uranohoshi Girls' Academy, which has the same peril as Otonokizaka Academy used to, until Chika, a huge fan of "Muse", decides to follow their example and gathers friends to form another group called "Aqua" for the sake of their school as well.