During the American Civil War, five northern prisoners of war decide to escape, during the siege of Richmond, Virginia, by hijacking a balloon. There is no safety visible beneath them, as the gas falls and the balloon loses altitude. The windswept, watery expanse presents not a single speck of solid surface upon which their anchor might hold. That they are riding in this gondola beneath the balloon is already an act of desperation -- for they are prisoners of war, who hit upon this mad scheme for aerial escape: the theft of the balloon moored and awaiting abatement of the storm, to ride...