Houkago no Pleiades: Prism Palette  

Wish Upon the Pleiades, 放課後のプレアデス Prism Palette

Subaru learns about her best friend Aoi's involvement in a magical group seeking engine fragments for an extraterrestrial being from Pleiades star system to return home. As the Pleiadian president has chosen her, Subaru contemplates joining the afterschool club.