On Astraea Hill stand 3 prestigious female-only academies known as St. Miatre, Spica, and LeRim; and though the schools are separate, they share a single campus and dormitory. Nagisa Aoi is a 10th grader who has decided to transfer to St. Miatre's Girls' Academy. Though her transition has been smooth so far, while exploring the campus Aoi inadvertently falls down a hill, sees the beautiful Shimuza, and promptly (not to mention embarrassingly) faints. Nagisa continues to see Shimuza out and about, but soon discovers that she is the "Etoile" -- a well respected girl within all of the schools. With Shizuma taking a liking to the new transfer student Nagisa, secrets of Shizuma's past will unravel over the coming school year.