After the Nazis invade Czechoslovakia, the developer of a new form of armor plating that may be key to the war effort, Dr. Axel Bomasch (James Harcourt), manages to escape to England. Unfortunately, his daughter Anna (Margaret Lockwood) is stopped by the Nazis and put into a concentration camp. She manages to escape with a fellow prisoner, Karl Marsen (Paul Henreid), but it's all a ruse meant to lead them to her father. After Anna and her father are kidnapped and taken back to Germany, British Agent Gus Bennett (Sir Rex Harrison), real name Dickie Randall, goes there impersonating a German officer with the aim of escorting them safely out of Germany.—garykmcd