A French agent, who is sent to save an atomic scientist, uncovers a plot by terrorists and a secret atomic site in Turkey.

Secret agent FX-18 goes undercover to break up an espionage ring.

The blueprints of an aeroplane built from an ultra-secret metal are stolen from national security. French secret service agent Walder believes that the documents are now in Switzerland, in the hands of a man named Lindbaum. The latter agrees to hand over the blueprints in return for a large sum of money. Another agent, Francis Coplan, is sent to Switzerland to handle the deal, but Lindbaum only has half of the documents because he was double-crossed by Kalpannen, an international crook. With the help of Heidi, a Swiss correspondent, Coplan sets out to identify the members of Kalpannen’s gang, only to find that they have all been murdered…

Free-lance undercover agent Coplan receives a phone call from an old girlfriend in Turkey. The panic-stricken woman gives sketchy details of a plot that threatens world security. When Coplan arrives, he is told the woman has been killed, and the trail of the murderer leads to her mad-scientist brother.

In a factory working for the National Defense, an employee steals a prototype. In charge of the investigation is Francis Coplan.

Secret Agent Francis Coplan, is given the task of finding priceless artwork stolen by the Nazis' in 1943. The trail leads to Mexico, where Coplan challenges a "secret" organization in order to re-gain the paintings.