Nick Carter va tout casser

World War I aviator Carbot attempts to establish a commercial airline after the war, for the purpose of delivering the mail to the outermost regions of France.

Between eleven o’clock and midnight one evening, a notorious trafficker Jérôme Vidauban is shot whilst walking in a tunnel in Paris. The case is assigned to Inspector Carrel, who is Vidauban’s perfect double. Using his resemblance to the arch criminal, Carrel manages to infiltrate in Vidauban’s circle of acquaintances and contacts. He becomes embroiled in a bizarre web of intrigue and discovers no shortage of possible murder suspects, all of whom appear to be surprised to see him still alive.

Lydia (Danielle Darrieux) is a student, poor and orphaned, who pretends to be the daughter of a famous writer.

Casablanca 1942. While French Police Chief Maurice Desjardins is busy having careless fun with some loose girls, members of the French Resistance kill a man at the harbor and steal his briefcase full of important documents from the Third Reich. At an apartment building in the distance, Andre Kuhn watches the whole operation through his powerful binoculars. He is posing as a businessman but actually working as a spy for the Germans a fact totally ignored by his live-in girlfriend Teresa Villar, a beautiful Spanish singer who works at El Dorado Night Club. Andre telephones Max von Stauffen, the head of German Intelligence in Casablanca, to inform him of what he has just witnessed. Max tells him to stay put until he arrives in order to get the information personally but, by the time he reaches Andres apartment, he finds him dead with a gun shot on his temple.

In a little town with a renowned college a female student is found after she was hogtied and strangled to death. Inspector Marco is assigned to catch the murderer.