Karen Aijou, a 16-year-old easygoing girl who has wanted to act on stage since she was a toddler, is one of the students. When her childhood friend Hikari Kagura goes to Seisho Academy, her passion for theater is rekindled. Karen discovers a hidden elevator going to a vast theater beneath the school thanks to an old acquaintance. This arena, hosted by a talking giraffe, serves as a battleground where her classmates compete in duels to determine who among them deserves the title of "Top Star," earning them the right to play one of the lead roles in "Starlight." Inspired by Hikari's promise to someday be stars together, Karen enters these mysterious battles in the hopes of making their dream a reality.