The Hochmann Miniatures — Robert L. Fish

To repay a wartime debt, a master smuggler ventures out into the open in this Edgar Awardâ€"nominated short story

The customs agent's eyes go wide when he reads the passport. It is Kek Huuygens, the notorious smuggler who has grown rich making border guards look like fools. Today he is returning from Switzerland, a box of chocolates packed in his briefcase. The guard confiscates the chocolates, which he is certain must contain diamonds, but he lets Huuygens keep the wrapper as proof of his purchase. Huuygens resists the urge to smile, for the wrapper contains a priceless piece of sheet music, written in Bach's own hand. He has beaten them once again.
 
He is toasting his triumph when a call comes through from Lisbon: an old friend from the war, when Huuygens waged guerilla warfare against the Nazis. The call leads to a peculiar reunion, and a chance for a coup that will remind every border agent in Europe why he curses the name Kek Huuygens.