The fortress was abandoned. The enemy was still inside.

•The Great Turkish War has turned Hungary and the Balkans into a battlefield.

Captain Matthias Falk is a disgraced Imperial officer with one last chance to salvage his reputation. His orders seem simple: approach the Ottoman fortress of Karadere and determine why its defenders have fallen silent.

Nine hundred Ottoman soldiers should be waiting behind its walls.

Instead, Falk finds an open gate, abandoned weapons, terrified horses—and not a single living defender.

Then the knocking begins beneath the fortress.

Men disappear from locked rooms. Corpses are discovered standing upright against the walls with their mouths packed with black earth. Soldiers return from the darkness looking exactly as they did before, except they do not bleed.

And they cast no shadows.

The Ottomans called them the Hollow Men.

When terrified survivors arrive at Karadere, Falk discovers the truth: the fortress was not abandoned because of the approaching Imperial army. Its defenders were fleeing something imprisoned beneath it—something ancient that steals men, wears their faces and speaks with the memories of the dead.

Now Imperial and Ottoman soldiers must fight side by side against an enemy that can look like anyone.

And beneath their feet, the seals of an ancient prison are beginning to break.

The Siege of the Hollow Men is Book Two of the Black Powder Horrors, a standalone military horror novel combining black-powder warfare, historical adventure, siege combat and supernatural terror during the Great Turkish War.