A heart so fierce and broken / Brigid Kemmerer.

Enhanced descriptions from Syndetics:

In the sequel to New York Times bestselling A Curse So Dark and Lonely , Brigid Kemmerer returns to the world of Emberfall in a lush fantasy where friends become foes and love blooms in the darkest of places.

Find the heir, win the crown.
The curse is finally broken, but Prince Rhen of Emberfall faces darker troubles still. Rumors circulate that he is not the true heir and that forbidden magic has been unleashed in Emberfall. Although Rhen has Harper by his side, his guardsman Grey is missing, leaving more questions than answers.

Win the crown, save the kingdom.
Grey may be the heir, but he doesn't want anyone to know his secret. On the run since he destroyed Lilith, he has no desire to challenge Rhen--until Karis Luran once again threatens to take Emberfall by force. Her own daughter Lia Mara sees the flaws in her mother's violent plan, but can she convince Grey to stand against Rhen, even for the good of Emberfall?

The heart-pounding, compulsively readable saga continues as loyalties are tested and new love blooms in a kingdom on the brink of war.

Reviews provided by Syndetics

Booklist Review

Harper, a girl from the mortal world, helped to break the curse holding the kingdom of Emberfall and Rhen, its prince, captive, but there's no happily ever after in sight. The breaking of the curse has unleashed a political maelstrom, complicating relations between Emberfall and its distrustful neighbors. And Grey, Rhen's guardsman and most loyal companion, has vanished--he has discovered the true heir to Emberfall and wants to spare Rhen the truth. But to Rhen, it seems as though Grey has betrayed him. And when Grey appears to ally with the queen of Syhl Shallow and her daughters, including the cunning Lia Mara, those fears are confirmed. While Harper and Rhen were the primary focus of A Curse So Dark and Lonely (2019), Grey and Lia Mara narrate the bulk of this second series entry, which leaves the Beauty and the Beast--style narrative in the first book behind for a more Arthurian story line here. Action packed, deeply romantic, and more focused than its predecessor, this volume creates more problems than it solves, keeping readers eagerly on the hook for the next installment.

Kirkus Book Review

A group of young people forge unexpected bonds that are tested when they must choose between love and duty.The enchantress's curse has been broken, but no happily-ever-after awaits Princess Harper and Prince Rhen; Rhen struggles with severe PTSD while rumors spread of an heir with magical abilities, weakening his claim to the throne. While the queen of Syhl Shallow regroups after a failed invasion, her elder daughter, 18-year-old Lia Mara, makes a doomed attempt to negotiate peace with Rhen. Meanwhile, Rhen's former guard commander, Grey, has been captured and questioned about his knowledge of the mysterious heir. When Rhen's conditioned fear of magic leads him to do the unthinkable, Lia Mara helps Grey escape. Their journey, told through alternating first-person perspectives, provides a Cook's tour of both countries, prompting thoughtful consideration of their distinct social and cultural traditionsand just enough time for romance to blossom. Like Harper in A Curse So Dark and Lonely (2019), Lia Mara proves herself the undisputed hero right up to the stunning conclusion. This sweeping, romantic epic repeatedly turns the tables on the fantasy tropes that readers might be expecting. Apart from Harper's brother's boyfriend, who is black, the majority of characters appear to be white; Harper has cerebral palsy.This nuanced sequel offers new perspectives and emphasizes the value and complexity of both sibling and romantic relationships. (map) (Fantasy. 13-18) Copyright Kirkus Reviews, used with permission.