In the glass castle ruled by a tyrant king with a heart as dark as night, assassin Celaena Sardothien wears the mask of his Champion. But beneath her lethal façade, her true mission remains hidden: to bring down the very empire she serves.

As whispers of rebellion echo through the halls, Celaena discovers she's not alone in her quest for justice. Secrets entwine with shadows, and trust becomes a dangerous game. Her loyalties are tested as those closest to her—Prince Dorian, Captain Chaol, and her dearest friend Nehemia—begin to question where her true allegiance lies.

When a harrowing tragedy strikes, the web of secrets unravels, and Celaena faces an impossible choice. To protect what she holds most dear, she must decide once and for all who she is willing to fight for... and who she is willing to betray.