Demobilised after the war in Algeria, legionnaire Franz Propp tries to get army doctor Dino Barran to go to the Congo with him. But Barran feels he has to help the beautiful Isabelle Moreau, whose lover he accidentally killed in Algeria. She wants him to take a job in a big firm in Paris, where his assistant will be an attractive girl called Dominique Austerlitz, and over the Christmas break to secretly return some missing documents to the safe.