Biology student Harry is kicked out of his research program. He does not understand why. What Harry don't know is that he has a double.
A scientist is persuaded by the government to inject himself with the brain fluid of a dying colleague in order to preserve missile-defense secrets. However, he finds that he is now torn between his own wife and that of his dead colleague, who was a Nazi sympathizer.
An FBI agent is killed by the mob after making off with five million in gold bars in a robbery gone bad. Agent Jerry Cotton is called in to bring the gang to justice and find out where his dead pal hid the missing gold.
Seeking revenge against the rival clan responsible for the killing, Hagbard, the son of a slain Norse king, calms down long enough to establish a truce. He also falls in love with Signe, the daughter of his one-time enemy. Signe's former beau, sizzling with jealousy, breaks the truce and makes it appear that Hagbard was responsible.