The Conspirators

Nazi authorities place a bounty on Vincent Van Der Lyn for his resistance activities. He is ordered to travel to England via the neutral port of Lisbon to continue his missions. The assignment marks him as a target for German and police attention.

Upon arrival in Lisbon, Captain Pereira notes that Van Der Lyn's passport lacks an exit stamp, suggesting a clandestine crossing. He is told that as long as the Portuguese visa is in order he can proceed. German agent Otto Lutzke becomes suspicious and begins tailing him.

In a Lisbon restaurant, a mysterious woman named Irene Von Mohr sits down at Van Der Lyn's table after a man in an alley is shot. She claims to be a frequent gambler at Casino Estoril and excuses herself to make a call, but she never returns. Her sudden appearance sows doubt and marks her as a potential ally or threat.

Van Der Lyn tracks Irene to the Casino Estoril where she warns him to stay away. Hugo Von Mohr, a German diplomatic official, and Lutzke join the scene, and the Germans quickly identify Van Der Lyn as the saboteur nicknamed the Flying Dutchman.

Van Der Lyn is introduced to Quintanilla and the underground group, including Jan Bernazsky, Anton Wynat, and Paulo Leiris. Quintanilla asks him to brief the replacement Jennings and privately hints that one member may be a traitor.

The next day Irene invites Van Der Lyn to ride with her, and they spend the day together. He confesses that he is in love with her, while she explains that she previously married Hugo after he rescued her from Dachau.

Back at his hotel, Jennings dies after delivering a message about an eagle. A false tip leads the police to arrest Van Der Lyn for Jennings's murder. Irene tells Captain Pereira that Van Der Lyn was with her all day but refuses to testify.

Van Der Lyn escapes from jail with Irene's help. She reveals herself as a resistance fighter and gives him a gun. They reunite with Quintanilla and the others, and Hugo is revealed to be part of the underground.

Quintanilla devises a trap by informing the group that Jennings's replacement will be at a casino hotel, anticipating the Germans will target him to plant their own agent. Captain Pereira is wary but agrees to wait for the real culprit to be revealed.

Fifteen minutes before the meeting, the group learns the new man's room number is 865. Hugo places bets on 8, 6, and 5, exposing himself as the traitor.

A pursuit ends in a shootout at the casino; Hugo is killed and the eagle is found in his pocket, resolving the dying message Jennings carried.

Van Der Lyn decides to return to occupied Europe in Jennings's place. Irene promises to wait for his safe passage, and he vows to come back to her.