Under Major Ransack's orders, a repugnant being who does not hesitate to loot and ruin the property of his victims, Chesterfield and Blutch accompanied by Chinese workers and a Scottish engineer will be delegated to repair a section of railway destroyed by the enemies. Before leaving, Chesterfield learns in a letter that two of his cousins enlisted in the army, but from the "bad" side: from the Southists! Arriving at the scene of the repair, the team is greeted by gunshots. The sergeant receives command from Major Ransack to silence this battery as soon as possible. But during the attack, what is not his surprise to discover that the two gunners are in fact only his two cousins.