Wish Upon the Pleiades

Subaru is a student who enjoys stargazing. During her free period, she enters the school's observatory and finds an unusual indoor garden instead of the expected equipment. There, she meets Minato, who mentions something odd before dismissing her. Later, Subaru encounters a small creature that runs off with her compass, leading her to stumble upon a club room where members are dressed in witch costumes, including her friend Aoi.

Subaru decides to join the club, where she's given a staff and undergoes a magical transformation by the creature, known as a Pleiadian. The club members, including Aoi, Itsuki, Hikaru, and Nanako, are searching for engine fragments from the Pleiadian's spaceship to help it return home. However, they're not the only ones seeking these fragments.