Seishou Music Academy's annual Seishou Festival is approaching, and the 99th class of girls are gearing up to showcase their performance of Starlight, a tragic tale of two goddesses whose unison is blemished by their inevitable separation. This girls-only institution strives to nurture young theatrical talent by refining the singing, dancing, and acting skills of its students. Karen Aijou, a 16-year-old student, has long craved the opportunity to grace the stage. Her affection for stage plays deepens when her childhood sweetheart, Hikari Kagura, transfers to Seishou Academy. Together, they discover an elevator that leads to a huge theatre concealed beneath the school. There, their classmates battle to attain the title of "Top Star" in a competition hosted by a talking giraffe to secure the right to play a lead role in Starlight. Karen takes up the challenge, driven by her determination to fulfil her dream of shining bright with her dear friend.