Heart of Winter (Knight of Avalon, #4)

Katie MacGregor has finally carved out the life she's always wanted. She's at her dream school, pursuing a medical degree, and rebuilding her life far from Faerie and the chaos of the Ogre War. But that peace is fragile. When a Winterborn assassin attacks her campus, everything shatters, pulling her back into a world she wants no part of.
High King Beri Quintinar, the love Katie worked so hard to forget, is struggling to hold the Unseelie Court together. With the Unseelie realm on the brink of collapse, Beri makes a desperate choice: he binds Katie to him through a magical ritual, reigniting unresolved feelings and forcing them to confront their shared history amid the growing chaos.
Complicating matters is Katie's budding relationship with Ushi Yamoto, the brilliant, enigmatic Wizard of the High Court. As their romance blossoms, Katie finds herself caught in a thorny tangle: her growing relationship with Ushi, the magnetic pull of the love she swore to leave behind, and the threat of Beri's looming political marriage, which could sever their bond forever.
Faerie itself is unraveling. The Yamoto Clan schemes to bring Ushi home even as Summer's rulers fight to abolish slavery and fend off Prince Glorian's advancing ogre armies. In the face of this turmoil, Katie and Beri must navigate fragile alliances to confront Faerie's enemies and their own complicated past.
With the fate of four realms hanging by a single thread, Katie and Beri must decide what they're willing to sacrifice to save Faerie-and each other.

The first novel Michelle John ever read was 'The Wizard of Oz' when she was six years old, and she has been fascinated by the intersection of fantasy and girl power ever since. As soon as she figured out the proper way to hold a pen she started writing stories about princesses who rescue dragons from evil princes. She hasn't yet found a reason to stop. Her style may have changed a bit since kindergarten, but in the twenty-five years of her career, she has never found a more interesting story to tell than that of a heroic young woman who saves the day.