In the Union camp, an extraordinary meeting of the General Staff is held to find a solution to shorten this civil war. The idea is to infiltrate a man of color acquired from the Northernists in the camp of the Southerners to weaken them by inciting them to revolt. For this perilous mission, Black Face is chosen. He will be escorted by Corporal Blutch and Sergeant Chesterfield. Unfortunately, they will be separated very quickly and then the situation will degenerate. Black Face organizes the uprising and quickly he will also turn against the Northernists. To put an end to this rebellion, General Alexander will have to appeal to Lieutenant Ripley, a racist torturer without the slightest state of soul.