After two Americans are killed while escaping from a German P.O.W. camp in World War II, the barracks black marketeer, J.J. Sefton, is suspected of being an informer.After two Americans are killed while escaping from a German P.O.W. camp in World War II, the barracks black marketeer, J.J. Sefton, is suspected of being an informer.After two Americans are killed while escaping from a German P.O.W. camp in World War II, the barracks black marketeer, J.J. Sefton, is suspected of being an informer.