The Silver Skulls Space Marine Chapter deploy on the world of Valoria Quintus to combat an insurrection backed by the dread forces of the Traitor Legions. Sent there by the visions of their Prognosticars, the mysterious psykers whose premonitions decree the path forged by the Chapter and the wars that they wage, they expect victory to be swift and easy. But they have not reckoned with their own allies, the servants of the Inquisition who are interested in the Prognosticars, their importance within the Chapter and the possibility that the Silver Skulls may be being manipulated by the very powers they fight against...

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They may be Ultramarines successors, but they're certainly not Codex-compliant... and the Inqusition wants to know why. How the Silver Skulls work and why it might just be their downfall is explored, with a series of shocking twists that will ensure that you never look at the silver-armoured Space Marines in the same way again.