At the end of World War II, an American task force investigates a Nazi project to reanimate the dead and summon strange monsters from other dimensions. Deranged by their own studies, the Nazi scientists have been difficult to find, much less talk to. Only the linguist Susan Gilbert has had any luck getting their cooperation. When it turns out that the biggest, most horrific experiment of them all has yet to be completed, she ends up leading the effort to save the world. But she's not a mad genius, not a secret agent, and not even in the military, and the only man with the knowledge to help her succeed is her own worst enemy, a remorseless, manipulative villain hunted by the Allies, the Nazis, and supernatural monsters alike.