Old Soldiers Never Die (Ciaphas Cain)

Inquisitor Amberley Vail opens the Cain Archive once again to present one of the strangest missions from the heroic commissar's storied career. Deployed to the world of Lentonia to police the aftermath of an insurrection, Cain and the Valhallan 597th have to deal with a dangerous disease spreading through the Astra Militarum ranks... an infection that kills its victims and returns them to life as flesh-eating zombies! As the dead rise across Lentonia, Cain and his malodorous aide Jurgen must seek a cure and find the source of the warp-tainted infection before they end up among the ranks of the walking dead themselves.

Read it because
It's a story of Ciaphas Cain vs zombies that was previously only available at Black Library Weekender 2012. Do you need any more reason? Oh, alright then, Cain vs zombies with a series of gorgeous illustrations of key scenes from the story. But mostly, Cain vs zombies.