DARK BREAKS THE DAWN

Graceling meets Swan Lake in this new duology from the author of the Defy trilogy that follows a young queen, Evelayn, as she comes into her powers in controlling Light, fights to overcome a rival leader who controls Dark, and attempts to bring together two warring kingdoms.

After thousands of years of peace between the Light and Dark Kingdoms of Lachalonia, King Bain is trying to seize control of Éadrolan (the Light Kingdom) to steal their power for himself. The war has lasted for ten years, with many casualties on both sides, including Evelayn's father, the king of Éadrolan.
Evelayn comes into her full power on her eighteenth birthday, and though she is excelling at learning to control and wield her newly released magic, she is unable to shift into her animal form, as only Royals are able to do. Her mother, the queen, isn't able to help her because she is at the warfront. She's also not there to talk to Evelayn about her growing feels for the new High Lord of the Delsachts—Lord Tanvir.
Shortly after her birthday, Evelayn's mother is also killed in battle by King Bain. The Light Draíolon retreat long enough for Evelayn to complete the ceremony that transfers the Light Power to her, as the new Queen of Éadrolan. If she fails, her people will remain powerless, and King Bain will be able to slaughter them without resistance. Evelayn channels her devastation and rage at her mother's death along with her new power and succeeds in reclaiming the power.
Now she must somehow figure out how to lead her people and stop King Bain. When a Dark Draíolon shows up at court, claiming to have key information to help her succeed in stopping his king, Evelayn decides to trust her instinct that he's telling the truth. Lord Tanvir agrees with her, and together, with her council of top generals, High Priestesses, and advisors, they devise a risky plan to defeat the king once and for all.
Evelayn hones all of her pain and anger and the incredible amount of power she now wields as Queen to lead her people to victory. She kills King Bain and imprisons Queen Abarrane and her two sons, Lorcan and Lothar. They are imprisoned until the three days have passed so that neither Lorcan nor Lothar can complete the ceremony and their magic doesn't transfer to either son. The Dark Draíolon are left weakened, nearly powerless. Evelayn knows there must be balance for their world—and the human world beyond—to survive, but she doesn't know if she can trust either son of King Bain. Once Lorcan swears a sacred oath to never come against the Light Draíolon again, Evelayn allows him to leave so he might journey to regain their lost power. She believes in balance and doesn't wish to rule both kingdoms. She just longs for peace.
Once Lorcan leaves, Evelayn plans a grand feast on the last night of Athrúfar—the harvest celebration before winter comes and the changing of the stronger power to the Dorjhalon kingdom. She has fallen in love during the entire ordeal with Lord Tanvir, whose parents were also killed in the war and they announce their impending Binding at the feast.
Right after they seal their betrothal with a special ceremony, the celebration is shattered by Lorcan returning. He tells Evelayn she must break her betrothal to Tanvir and wed him instead, giving herself to him so that he might access her power and rule both of their kingdoms if she wants to maintain the peace. She refuses, not believing herself susceptible to his threats, but when she tries to block his attacks, she realizes she is weakened somehow. He kills Tanvir and attacks her again. He is able to do what she hasn't been able to accomplish—he forces her to assume her shapeshifting form—a swan—and carves her conduit stone out of her chest. Her kingdom's power is lost and King Lorcan claims control of both.