On the world of Khorion IX, daemonhunter Mandulis of the Grey Knights is locked in a titanic battle with the daemon prince Ghargatuloth. In a fight that costs him his life, Mandulis manages to banish the foul daemon back to the warp for a thousand years. A millennium later Justicar Alaric of the Grey Knights leads an elite team of his brothers to put paid to a prophecy which heralds Ghargatuloth's return.