Book three of the Ciaphas Cain series.

An old rival, infighting with fellow Astra Militarum regiments and the small matter of a cult devoted to the Chaos God Slaanesh derail Commissar Cain's hope for a quiet and uneventful mission.

Ciaphas Cain's latest mission takes him and his Valhallan regiment to the planet of Adumbria to defend against an approaching Chaos invasion. However, infighting with fellow Imperial Guard regiments from the world of Tallarn, commanded by an old 'friend' of Cain's from the Schola Progenium and the uprising of a sinister cult on the planet puts paid to any hopes of an easy life.