When Inquisitor Grinner investigates an abandoned Imperial merchant ship adrift in the Halo Stars, he and his operatives discover that everyone on board is dead, apparently killed by a powerful psyker. Since the ship left the Calixis sector, he contacts his colleague, Inquisitor Karl, who launches a network of agents into this area. But there is no such thing as an easy inquisitorial investigation, and Carl and his team soon find themselves in deep trouble. The smugglers' operations turn out to be more dangerous than they seem, whether the inquisitors can uncover their dark secrets before they themselves are destroyed.