The movie opens with the voice of Professor Broom (John Hurt) asking a question that will shadow the rest of the film: "What is it that makes a man 'a man'? Is it his origins- the way things start"??? The voiceover goes on to give some backstory: it is 1944, nearing the end of World War 2, and Hitler is resorting to the occult in a desperate attempt to turn the tide of war in his favor.
The scene opens on an island off the coast of Scotland, where young Professor Broom requests that the military personnel be given rosary beads before continuing on the assignment. But the sergeant in charge just laughs at Broom, thinking him a paranoid moron.
American troops arrive at a set of ruins and find a group of Nazi scientists led by Rasputin and his mistress, IIsa. They are protected by a mysterious figure in a gas mask named Kroenen, reportedly Hitler's top assasain.
Rasputin attaches himself to a mysterious device designed to open a portal to another dimension and awaken forces known as "The Seven Gods of Chaos." Just as the portal opens, the American troops launch grenades into the site, killing some scientists.
Kroenen attacks the Americans, killing several and wounding Professor Broom in the leg. Broom crawls over to a fallen soldier and picks up a grenade, hurling it just beneath the portal. Kroenen breaks off his attack and tries to remove the grenade, but cannot get to it in time. The grenade explodes, destroying the portal and Kroenan's right hand. Kroenen is then impaled by a fragment from the portal and is presumed dead. Rasputin is unexpectedly sucked into the portal, closing it.