Set in a German POW Camp for enlisted American airmen, a spy is discovered to be living in one of the prison barracks after an escape attempt fails resulting in the deaths of two inmates. The prisoners at once suspect Sefton, an unscrupulous inside dealer who trades almost anything with the Germans for extra privileges. After Sefton is beaten up, he himself determines to find the real spy and the result is a mixture of intrigue and betrayal leading to a surprise ending.