July 1792, 12 year-old Armand-Pierre and his two friends Jean and André attend Abbé Pessonneau's class where he congratulates them for singing La Marseillaise when the revolutionary army was marching towards Paris. Meanwhile, young lawyer François Ducoureau decides to enlist and go to Paris too, which saddens his fiancée Marie Laporte, daughter of the local baker. The three kids follow his path and escape from the village, soon followed by Pessonneau and one of the boy's father who try to bring them back without ever catching them up. When the two men return to tell Armand's mother that the kids managed to enlist, she accuses them of child abduction. During the battle of Valmy, young Armand is supposed to stand guard at night and play his drums should the enemy come. He is killed in action but saves the company thanks to his bravery. During Pessonneau's trial, Armand's mother understands his sacrifice and finally asks the judge to release the accused. The next day, all of Armand's classmates gather to pay their homage to his mother. She offers Armand's drumsticks to one of the boys and tells him that if he ever is unable to play, another boy will do it, and then another, as long as France will last.