During the Second World War, in 1943, two French prisoners, François and Michel, escape from Stalag B377 in northern Germany near the Baltic Sea. They meet another escaped compatriot, Pierre, who has donned the uniform of a German officer and joins them. Their goal: to reach neutral Sweden. To get there, they'll have to walk part of the way, then take a train to the coast and, from there, find a way to cross the sea to the shores of Sweden.