Captain Elliott Parrish of Her Majesty’s 17th Lancers cavalry division finds most details about his assignment in the Crimean Peninsula insufferable. Rampant cholera, missing supplies, and inept planning start the British war effort against the Russian Czar’s expansion into Turkish territory on poor footing.

What should have been a swift and decisive summer victory soon drags into a harrowing winter campaign, and Elliott must rally disheartened men through sickness, battle, and starvation. But when he is assigned the additional task of spying on a fellow officer, the inscrutable Cornet Ilyas Kovakin, he finds himself disconcerted and fascinated by both the work and the man.

Rumors surround Ilyas Kovakin, the half-Russian officer who reports to none in his division. People say they’ve seen snakes slithering into his tent at night, that he has another face visible only in certain light, and a penchant for violent acts carried out in darkness, alone. But the truth that Elliot soon discovers is much more dangerous than mere superstition.

For Ilyas, his return to Crimea is colored with the horrors of his past. Once a mercenary, he has made a terrible mistake and inherited horrifying powers that he can barely control. He feels his hold over his humanity slipping away daily, and fears that salvation may already lay beyond him when the cheerful Captain Parrish catches his attention. Among men who hate him and superiors who covet his brutal power, Ilyas finds the young captain's charming company almost irresistible.

But Ilyas knows that the closer he is drawn to Elliott the more he will endanger them both.