Zodiac Academy #1 The Awakening (original) Caroline Peckham

you're one of the Fae, elemental magic is in your blood. And apparently it's in ours. As twins born in the month of Gemini, we're a rare breed even in this academy of supernatural a-holes.

Changelings were outlawed hundreds of years ago but I guess our birth parents didn't get the memo. Which means we're totally unprepared for the ruthless world of Fae.