In November of 1942, the French submarine, the "Casabianca,", escapes from German-held Toulon, and, upon joining the Free French forces at Algiers, is sent on a secret mission to Corsica to take two secret-service agents to make contact with the underground there. The agents contact the Marquis resistance forces, and learn they are ready to revolt but lack the needed arms and ammunition. The submarine is sent back to Corscia with the necessary weapons for the resistance-fighters, and also returns with trained troops to assist the resistance forces in attacking the Germans.

During the second World War. The lives of three comrades fighting in the Forces Françaises Libres' flight. Pierre is a valiant pilot, afraid of nothing. Jean is reported missing during the Normandy landings. Jacques gets killed on the very last day of the conflict, leaving behind him a weeping widow.

A young pilot, Martin, applies for the Ecole Militaire de Salon. He is accused of having caused the accident of one of his bosses, his career is then threatened.

The local building-contractor Martin Roumagnac is fascinated by the fashionable Blanche Ferrand. To impress Blache, Martin presents her with a villa. However, this ruins him financially. Despite Martin's many efforts for the now femme-fatal Blanche, she is not able to chose between him and the rich consul De Laubry.

The exploits of Chief Police Inspector Chabrier, first before the invasion of France in May 1940 as he fights against spies preparing the coming the Germans, particularly Emmy de Welder, the alleged manager of the Rouen hospital. Later, Chabrier and his men go underground and resist the occupiers whatever the price to pay. When the Liberation comes Chabrier resumes his activities at the French National Police.