Beyond the Martial Empire and within it, the threat of war looms ever larger. Helene Aquilla, the Blood Shrike, is desperate to protect her sister's life and the lives of everyone in the Empire. Yet danger lurks on all sides. Emperor Marcus, haunted by his past, grows increasingly unstable and violent, while Keris Veturia, the ruthless Commandant, capitalizes on the Emperor's volatility to grow her own power—regardless of the carnage she leaves in her path. Far to the east, Laia of Serra knows that the fate of the world lies not in the machinations of the Martial court, but in stopping the Nightbringer. During the hunt to bring him down, Laia faces unexpected threats from those she hoped would help her, and is drawn into a battle she never thought she'd have to fight. And in the land between the living and the dead, Elias Veturius has given up his freedom to serve as Soul Catcher. However, in doing so, he has vowed himself to an ancient power that demands his complete surrender—even if that means abandoning the woman he loves.

Beyond the Martial Empire and within it, the threat of war looms ever larger. Helene Aquilla, the Blood Shrike, is desperate to protect her sister's life and the lives of everyone in the Empire. Yet danger lurks on all sides. Emperor Marcus, haunted by his past, grows increasingly unstable and violent, while Keris Veturia, the ruthless Commandant, capitalizes on the Emperor's volatility to grow her own power—regardless of the carnage she leaves in her path. Far to the east, Laia of Serra knows that the fate of the world lies not in the machinations of the Martial court, but in stopping the Nightbringer. During the hunt to bring him down, Laia faces unexpected threats from those she hoped would help her, and is drawn into a battle she never thought she'd have to fight. And in the land between the living and the dead, Elias Veturius has given up his freedom to serve as Soul Catcher. However, in doing so, he has vowed himself to an ancient power that demands his complete surrender—even if that means abandoning the woman he loves.

Elias and Laia are running for their lives. After the events of the Fourth Trial, Martial soldiers hunt the two fugitives as they flee the city of Serra and undertake a perilous journey through the heart of the Empire. Laia is determined to break into Kauf—the Empire’s most secure and dangerous prison—to save her brother, who is the key to the Scholars’ survival. And Elias is determined to help Laia succeed, even if it means giving up his last chance at freedom. But dark forces, human and otherworldly, work against Laia and Elias. The pair must fight every step of the way to outsmart their enemies: the bloodthirsty Emperor Marcus, the merciless Commandant, the sadistic Warden of Kauf, and, most heartbreaking of all, Helene—Elias’s former friend and the Empire’s newest Blood Shrike. Bound to Marcus’s will, Helene faces a torturous mission of her own—one that might destroy her: find the traitor Elias Veturius and the Scholar slave who helped him escape…and kill them both.