After Uranohoshi Girls' High School closed, the third-year cohort—Dia Kurosawa, Kanan Matsuura and Mari Ohara—just finished their studies, leaving Aqours with only first- and second-year members. While looking for a new practice venue, the remaining singers head to the school they will soon join. To their astonishment, the building appears deserted! It turns out that the school board feared the newly transferred Uranohoshi students might strain club activities, so they were redirected to a satellite campus. This prompts Aqours to set a new mission—to demonstrate that Uranohoshi pupils are equally dedicated to their clubs. Meanwhile, another issue surfaces: the third-years vanish during their graduation excursion! During this journey, they must also confront their own doubts about the future while keeping hope alive. Additionally, they uncover hidden talents that could change the club"s dynamics forever. Their determination remains unwavering. Love Live! Sunshine!! The School Idol Movie: Over the Rainbow focuses on Aqours" remaining members as they search for their missing seniors and simultaneously attempt to persuade the new school"s administration.
