Claude Orval

Two state employees, Molot and Maurent, are very fond of detective stories. They open a private eyes agency, which only opens on Sundays. But the clients are rare, and some kind of Arsène Lupin steals their savings. They set out to track so called suspects down but everything backfires on them; however,one fine day, a man knocks on their door: he asks them to shadow his fiancee who may (or may not) be true to him. Maurent falls for her.

Robert Vernier is assigned by the Secret Service to unmask a band of gangsters determined to get their hands on the plans for a new plane. They manage to steal part of it and kidnap Robert's fiancée, named Monique. Robert will manage to dismantle the gang and will be surprised to find that at the head there is a policeman...

Jacques Hélian, an attractive charm singer, too stifled by the jealousy of the radio director's niece, flees with his orchestra, on the advice of his secretary Bob. They fail in a small village, where there is a boarding school for young girls. Bob responds to the love letters the teacher sends to the handsome singer.

Commissioner Thomas simultaneously investigates the actions of an oil company, a theft and an assassination, and the kidnapping of a child with look-alikes.

A group of political exiles conspire in France against their government. They are pursued by Daminoff, head of the intelligence service of the country of origin of the conspirators, who uses Nadia, a singer who soon betrays him by taking up the cause of his compatriots. Dramatic chases ensue until Daminoff, having tracked down Nadia and her friends, fires on Chief André and seizes the secret plans. But these are false. André, injured, is stricken with amnesia. Seeing Nadia again, he will become himself again and marry her.

Inspector Doirel investigates the murder of a man whose servant was found tied up. He discovers very quickly that the servant has lied. The latter ends up denouncing his accomplice who is arrested when he was going to kill the informer.