When the flow of desperately needed weapons for the Astra Militarum slows to nothing from a newly founded forge world, there's only one man able and (un)willing to investigate...

Ciaphas Cain, Hero of the Imperium. With Cain's desperately sought-after retirement on the line, the Imperium's most reluctant commissar must navigate insidious assassination attempts against his person, legions of mutinous skitarii, heresy within the upper echelons of the Adeptus Mechanicus itself... and a hidden foe, pulling the strings, with an agenda that could threaten the future of Imperial rule in the Damocles Gulf.