The Cruel Prince

Jude Duarte, a mortal girl taken into Faerie as a child after General Madoc murdered her parents, spent the book scrabbling for status in a court that scorns humans. Alongside her twin sister Taryn, she was tormented by Prince Cardan and his circle, killed his crony Valerian in self-defense, and was recruited by Prince Dain — the presumed heir to the High King — into his secret ring of spies and assassins, the Court of Shadows (which includes operatives called the Roach, the Bomb, and the Ghost). In exchange for future status, Jude spied, blackmailed, and fought her way into real influence, and at one point privately forced Cardan to swear an unbreakable faerie oath to obey a future command from her.

Everything came to a head at the ceremony where the dying High King Eldred was to name his heir. Against expectation, he named Cardan rather than Dain. Refusing to accept this, Dain tried to seize the crown by force and was killed in the resulting massacre, along with other members of the royal family. Cardan's abusive older brother Balekin, seeing the surviving heirs eliminated, planned to let Cardan take the crown and then rule through him as a puppet. Jude was poisoned in the violence but survived because of a poison tolerance she'd built up over years, and in the ceremony's aftermath she invoked Cardan's oath, forcing him to name her his Seneschal — the second-most-powerful office in the realm. Using that authority, she had Balekin imprisoned in the Tower of Forgetting, undoing his plan.

The book ends with Cardan crowned High King of Faerie but magically bound to obey Jude for a fixed length of time, making her the real power behind his throne even as the wider court despises and distrusts her. Loose threads going into the next book: Jude now effectively rules Faerie from the shadows through a resentful, unpredictable Cardan who was forced into this arrangement against his will; Balekin is imprisoned but not necessarily neutralized as a threat; Jude's relationship with her adoptive father Madoc remains tense and unresolved, since he is ambitious and not fully trustworthy; her sister Taryn has become engaged to Locke, the fae noble who had also romantically pursued Jude as part of a game, straining the sisters' relationship; and their half-sister Vivi's mortal girlfriend Heather has been drawn into the human world's exposure to Faerie's existence, an unresolved complication. The Court of Shadows spies Jude worked with survived the coronation massacre and remain part of her network.