To dislodge the Southists cut off in an inexpugable camp, General Grant has a good idea. But his plan, to dig a gallery under their camp to blow up barrels of powder, made long fire and the leader of the Blues plunges again into the bottle. Excessed, Lincoln sends one of his spies to investigate, ready to undermine the alcoholic general. Blutch and Chesterfield will have to compete with ingenuity to bring their general back in the right direction while foiling the plans of this spy nicknamed " Lincoln's Ear"...