The Trouble with Magic and Faery Curses - Cary Redmond, #5

Trouble's in the Curses. Halfway through her test year as a magical Protector, Cary Redmond is starting to think she just might survive. With her leopard shifter mate at her side, she's even managed to enjoy parts of the journey. Then her latest job reveals trouble brewing in Faery. Trouble that could affect all the realms and seriously complicate her test year. The path of danger points to the English Faery court-and her former mentor, Jaxer.
She wants to help her friend, even though their current relationship can best be described as complicated. But stepping into a realm made entirely of magic, when she's just discovered she can absorb magic, seems like a bad idea. Especially since she hasn't learned how to release that magic yet. With a world-ending threat looming, even Cary's bosses want her to go. And she won't be going alone. Both her mate and her mentor will be at her back.
But to save the world this time, Cary has to confront her greatest fears. And the knowledge that if she fails. Her own realm will fall.