Rowan and Citra are gone, Endura has disappeared, and now, it seems, nothing can stop Scythe Goddard from obtaining absolute rule of the world of scythedom. The Thunderhead's silence, the Great Resonance, both still shaking the earth--the only way to stop it all lies in the Tone, the Toll, and the Thunder as humanity struggles in a world that has conquered death to stop the immortal beings they have accidentally created.