London 1861. William Russell, a journalist at the Times, is covering a strike in a factory, to the great disdain of his superiors who accuse him of setting himself on the side of the workers. To get rid of him, the newspaper editor sent him to the other side of the Atlantic where the Civil War was raging. In America, in the camp of the Northern army, Corporal Blutch and Sergeant Chesterfield were in charge of escorting this funny, frivolous and distinguished English observer, who took notes on the battlefield by riding a mule.