Much of the action of the story takes place inside the Soviet Union, commencing with Russia entering the war against Nazi Germany. There to counter Gregory Sallust's plans is his arch-enemy, Gruppenfuhrer Grauber, as anxious as ever to settle the longstanding score which has existed between them, and as plot and counter-plot carry the story into a Swiss lakeside villa, the final scenes are played out in a sinister castle situated deep in the heart of a German forest.