This latest system update to Dark Heresy 2.0 perpetuates the science fantasy (as opposed to science fiction) of the Warhammer Universe, but unlike earlier attempts to provide players and gm's with useful tools for creating engaging sessions I believe that Enemies Within is a solid step in the Right direction. While not nearly as robust in its gm toolkit as systems like Stars Without Number, this book none-the-less provides gm's with setting-appropriate adventures in the vein of the Abnett's Eisenhorn stories and Sandy Mitchell's "Innocence Proves Nothing." To me, the most engaging stories of 40k's grimdark are the those where ill- or mis-informed but no less goodly and skilled servants of the Imperium carry their torch into the deep and the dark places, look into the madness that therein dwells, and fight feverishly to burn out that rot with cleansing flame, and this supplement, more than any other fantasy flight has since put out, is their best effort to allow players fulfill that fantasy.