After seven long years of conflict, the Horus Heresy nears its end. But now, as the Warmaster Horus marches on Terra to rip his father from the Throne, the seat of the arch-traitor’s power lies empty. Cthonia, a world once dominated by brutal murder-gangs, is occupied by the Emperor’s praetorians—the indomitable Imperial Fists. For the Sons of Horus, this outrage demands a reckoning.

The wind screams. The dark night is freezing. Vossk, a Vostroyan Firstborn, shrinks into a rock against a howl of memories. Having disgraced himself by deserting his post during a terrifying encounter, Vossk had resigned himself to penal servitude, though yearned for the chance to redeem himself. But in the 41st Millennium, such dreams are hollow when a man’s reality has been shaken to his core. Found in the shadows of a pitiless cave, Vossk relives his tale to his rescuer....

For Ianthe, war is all too familiar. A former soldier in the Astra Militarum, she now serves Inquisitor Covenant as an agent of the Throne. Her first mission sees her investigating a cult called the Children of Eternity. Falling foul of the local Enforcers, Ianthe soon learns that war in the shadows is seldom straightforward and that the local, angry law-keepers are the least of her troubles.

For a thousand years, the Sabbat Worlds have been lost to the Imperium, claimed by the dread powers of Chaos. Now, a mighty crusade seeks to return the sector to Imperial rule. And at the forefront of that crusade are Colonel-Commissar Ibram Gaunt and the Tanith First and Only - better known as Gaunt’s Ghosts. Trapped in the grinding trench warfare of Fortis Binary, the Ghosts find themselves drawn into a conspiracy to assassinate the crusade’s leader, Warmaster Macaroth.

In the far reaches of Imperial space, a ferocious warp storm approaches an Administratum world, cutting off the entire planet from the rest of the Imperium. As their towering grey spires are punished by endless rain, countless administrators, tithe-masters, and book-keepers are forced to evacuate. Among them is Greta, a lowly data-drone with a terrible secret, wanted for questioning by the sadistic Imperial interrogator Stefan Crucius. As disaster strikes and the pair are left stranded in the depths of the drowning city, captor and captive must cooperate.