In the tense days before World War II, Katie O'Hara, Ginger Rogers, an American burlesque performer posing as the socialite Katherine Butt-Smith, is poised to marry Austrian Baron Franz Von Luber, Walter Slezak. A sharp-eyed foreign correspondent, Pat O'Toole, Cary Grant, suspects the Baron of Nazi sympathies and tries to pry information from Katie, only to be warned off by the wary aristocrat.
Undeterred, O'Toole shadows the couple to Prague, where Katie and the Baron marry. After the Germans seize Czechoslovakia, the Lubers press on to Warsaw, where Von Luber begins selling arms to Polish General Borelski, Albert Bassermann. O'Toole cautions the General about trusting Von Luber, but intrigue thickens as the General tests the weapons and discovers they are dud. The Baron’s deceit is exposed, and suspicion falls on him when the Germans invade Poland. He is arrested on that suspicion, yet he warns his young bride not to worry because, as he cryptically puts it, no one will be able to bear witness against him.
> No one will be able to bear witness against him.
Meanwhile, the General’s planned action spirals into tragedy: the General is assassinated along with a young Nazi the Baron has chosen to sacrifice. With Von Luber behind bars, Katie and Pat resolve to flee, but the escape is complicated: Katie has entrusted her passport to her Jewish maid, Anna, Natasha Lytess, ensuring the woman and her two children can flee the country too. The duo’s escape route snakes through Norway, the Netherlands, Belgium, and Paris, all slipping under the shadow of advancing German control, aided covertly by Von Luber.
In Paris, the plot thickens when they encounter Gaston Le Blanc, Albert Dekker, an American counterintelligence agent posing as a photographer. Le Blanc convinces Katie to return to the Baron and work as a spy on his behalf, a risky turn that unsettles the fragile alliance between love and loyalty. Von Luber grows increasingly suspicious of Katie’s inquiries, while Pat O'Toole waters the line between duty and desire. At a critical juncture, Pat agrees to broadcast pro-Nazi propaganda after the Baron threatens to turn Katie over to the Gestapo, pulling the stakes higher than ever.
American counterintelligence then reaches out to O'Toole with a second, dangerous option: betray the Baron. The tension erupts when Katie is found with Le Blanc, who is shot by two Nazi agents, and Anna steps in to help Katie escape from captivity. O'Toole goes on the air, but Katie’s sudden appearance in the studio sets off a calculated gambit. O'Toole orchestrates a ruse that the Baron is attempting to overthrow Hitler, turning the broadcast into a strategic move rather than a confession.
Von Luber is arrested, and Pat and Katie seize a chance to slip away again. They board a ship bound for America, but fate intervenes when Katie unexpectedly encounters Von Luber aboard. The Baron manages to talk his way out of immediate danger and continues his subversive plans as the ship heads toward the United States. A struggle ensues, and Von Luber falls overboard. Katie’s warning about his fate—combined with the Captain’s instinct to keep the ship steady—leads to a dramatic moment: the Captain turns the vessel around to search for his body, only to be reminded by Katie that Von Luber cannot swim, and the ship reluctantly retraces its course toward safety and home.
Throughout the voyage and the perilous international chase, the film threads together themes of deception, loyalty, and the murky line between romance and espionage. The characters’ choices ripple outward, shaping the fate of those who crave freedom in a world tipping toward total war, and they leave the audience with a taut sense of how personal motives intersect with historical catastrophe.
