In the campaign, Allied agents from the fictional "Office of Secret Actions" (OSA) are sent to investigate rumors surrounding one of Heinrich Himmler's personal projects, the SS Paranormal Division (also see Ahnenerbe). The agents are, however, captured before completing their mission and are imprisoned in Castle Wolfenstein. Taking the role of Blazkowicz, the player must escape the castle. The player soon investigates the activities of the SS Paranormal Division, which include research on resurrecting corpses and biotechnology, while also sabotaging weapons of mass destruction such as V-2 rockets and biological warheads. During the game the player battles Waffen SS soldiers, elite "Fallschirmjäger" (paratroopers) known as Black Guards, undead creatures, and "Übersoldaten" (supersoldiers) formed from a blend of surgery and chemical engineering conducted by Wilhelm "Deathshead" Strasse. The end boss is an undead Saxon warrior-prince named Heinrich I.