During World War II, former schoolteacher turned Dutch resistance fighter Vincent Van Der Lyn (Paul Henreid) causes so much trouble for the Nazis, they place a bounty on his head. As a result, he is ordered to travel to England by way of neutral Lisbon. On Van Der Lyn's arrival, Police Captain Pereira (Joseph Calleia) notes that his passport has no exit stamp on it (indicating he sneaked across the border), but reassures the traveler that all that matters is that the Portuguese visa is in order. German agent Otto Lutzke (Kurt Katch) becomes suspicious and starts following the Dutchman.