 During WWII, in Stalag (which is German for prison) 17, the prisoners are dumbfounded as to how the Germans know when someone s trying to escape. Recently, two tried to escape and never made past just outside the camp. Sefton, a hustler and wheeler dealer, said that they wouldn t. And it also seems that Sefton doesn t mind that he has to trade with the Germans for some extra food or whatever and has no desire to escape. When they lose some valuable materials like a radio, or when a Lieutenant Dunbar, who just arrived, and who also blew up an ammunition train, and who also has some (unpleasant) history with Sefton, is arrested, they assume that Sefton s an informant. And while Sefton adamantly claims he is not, they don t turn their back on him or trust him, and would like nothing better than to tear him apart. Can Sefton find out who the real informant is?