In the shadows of the Empire, on remote worlds and in vast megacities, the Inquisitors of the Empire carry out their work – searching for traitors, witches, and aliens. Gregor Eisenhorn is one such Inquisitor, investigating cases that range from strange murders to the machinations of interstellar organizations. However, what initially seems unrelated ultimately reveals itself to be a threatening conspiracy surrounding a non-human text known as the Necroteuch. As the trail leads him deeper into the world of heretics and criminals, he increasingly strays from the strict guidelines of the Inquisition and ultimately draws the wrath of the Empire upon himself. In his quest to uncover the masterminds of a cabal that threatens entire sectors of the Empire, Eisenhorn engages in a cat-and-mouse game where it becomes increasingly difficult to distinguish friend from foe. An Inquisition novel.