Meet Indy Barbaro, a centaur battle smith artificer who is an orphan (urchin background) living at a boarding school in the city. One day she finds a strange mouse in the room she shares with her rich satyr roommate that begins speaking with them and shows them the magical world of being magical girls. The magical girl transformation gives each of the girls unique powers. Indy is able to summon her steel defender, a full horse, and gains abilities to create magical items (and also bonk people pretty hard). But wait there’s more - when they transform, the girls also plane shift to the feywilds, revealing the true nature of those around them.
Indy, her roommate (a paladin once transformed), and their other new magical girl friends (a dryad druid (the baby one) and a pixie rogue (the edgy one)) realize there are creatures from the infernal planes showing up at the school. While fighting these beings, the girls uncover that the archdevil Asmodeus has been conjuring creatures from the Nine Hells in the feywilds for one reason: his child was unable to make it into the boarding school. Now the girls must defeat Asmodeus and his lackeys all while navigating the ins and outs of being in high school.