Burning Crowns (Twin Crowns, #3) by Katherine Webber

Twin queens Rose & Wren survived the Battle for Anadawn and brought back magic to their kingdom. But danger lurks in Eana’s shadows.

Wren is troubled. Ever since she performed the blood spell on Prince Ansel, her magic has become unruly. Worse, the spell created a link between Wren and the very man she’s trying to forget: Icy King Alarik of Gevra. A curse is eating away at both of them. To fix it they must journey to the northern mountains—under the watchful guard of Captain Tor Iversen—to consult with the Healer on High.

Rose is haunted. Waking one night to find her undead ancestor Oonagh Starcrest by her bed, she receives a warning: surrender the throne—or face a war that will destroy Eana. With nowhere to turn and desperate to find a weapon to defeat Oonagh, Rose seeks help from Shen-Lo in the Sunkissed Kingdom, but what she finds there may break her heart.

As Oonagh threatens all Rose and Wren hold dear, it will take everything they have to save Eana–including a sacrifice they may not be prepared to make.