In 1940, when the German army launched the offensive, they joined Normandy. Gerard is not long in getting incorporated. Soon, without a fight, he is taken prisoner but escapes two days later. After the armistice, he worked near Tarbes, in an unoccupied zone at "Chantiers de la Jeunesse".  For his part, the young Bernard is emancipated at 17 to be able to engage. He left for the south of France and then Marseille tries to reach Africa. An aborted attempt after the explosion of the boat. At the time of the demobilization in 1941, the two brothers meet again in Lyon, where the resistance network is very active, then go back to Roncq, where they find their family at the end of the year 1941.

They are always ready to leave to serve France. It is in September 1943 that they are called. They go south to walk the Pyrenees. They are denounced and taken prisoner at the camp of Miranda de Ebro (in the north of Spain). By pretending to be French-speaking Canadians with the American consul and the Red Cross, they are released and join Casablanca.

In 1944, they managed through General De Lattre de Tassigny to become paratroopers. While the parachuting must be postponed because of the weather, Bernard died brutally on July 20, 1944, at age 21, in Algiers. A tragedy for his brother Gérard, who will die nearly four months later. After many exploits. He participated in the liberation of Montélimar, Valence, Grenoble, to Maurienne where he spent 27 days and participated in 24 fights. He died during a battle on the night of 8 to 9 October, at the most critical hours there were only ten French soldiers against 300 Germans. He was 24 years old. Gérard Bonduel received the Legion of Honor posthumously.