Indy and his girlfriend, Nancy Stratemeyer (whose father created the Nancy Drew mystery series) visit the fascinating laboratory of inventor Thomas Edison and they must contend with dangerous German spies, as they try to keep Edison's top-secret invention safe.

In Russia, Indy's espionage work threatens more lives when he infiltrates a group of young Bolsheviks and begins to sympathize with their plight, and causes Indy to question his loyalty.