Damnatus: The Enemy Within (or to give it its original German name, Damnatus: Der Feind Im Innern) is a fan film set in the universe of Warhammer 40K. It follows a small team of mercenaries recruited by the Imperial inquisition as they attempt to infiltrate a suspected Chaos cult on the planet of Sancta Heroica. It appears that a rogue inquisitor is behind the cult and is attempting to summon a daemon for his own purposes, but the plot goes deeper than that, and it is not long before the heroes find themselves in way over their heads.