Former OSS officer Alan Holiday (Leslie Nielsen), now living in London, is visited on New Year's Eve by Catherine Carrel (Alizia Gur) who says she is a close friend of Jules Lemoine (Hugh Latimer) who served with Holiday during the war. Lemoine urgently requests that Holiday go to Paris on a secret mission. Lemoine visits and wants Alan to deliver a reel of tape which he gives him, and keeps a fake reel himself to deceive enemy agents. Lemoine is killed and the fake tape stolen. Holiday, poses as an assistant to photographer Louis Vernay (Andre Marrane), and they take three models along to further the ruse.

Alan Holiday, a former OSS officer now living in London, is visited on New Year's Eve by Catherine Carrel, who claims to be a close friend of Jules Lemoine, one of Alan's wartime colleagues. Lemoine wants Alan to deliver a tape recording containing secret defense information to the French government. After receiving the tape from Lemoine, Alan poses as a photographer's assistant and leaves on the boat train to Paris with Catherine, who is masquerading as a model. Before their departure, Lemoine is murdered by a counterintelligence agent who, unable to find the tape, also boards the train. Because of the confusion of a wild New Year's party, Alan is able to elude the assassin until the train reaches France, but once there, he is confronted by another counterespionage agent seeking the tape. Although Alan escapes, he is stopped by Catherine, who, it develops, is also in league with the foreign agents; but he disarms her and turns her over to the police, along with the vital tape recording.