The Purge Behind a Loyal Mask

"The Shadow Crusade spreads across Ultramar, with the Word Bearers 34th Company falling upon the isolated world of Percepton Primus. As the fighting draws out into a programme of extermination, embittered commander Sor Talgron begins to question his part in Lorgar's grander scheme - for one who stood beside primarchs and high lords in the grand halls of the Imperial Palace, what glory can there now be in punishing Guilliman's upstart sons? But the price of doubt is known all too well, and if the Word Bearers are ever to return to Terra in triumph then they must purge the last remnants of such unbelief from the face of the galaxy"--Publisher's description.