In the midst of the Second World War, Anna Neagle delivers a careful, unsettling performance as Sally Maitland, a woman whose apparent devotion to the Nazi cause masks a sharp, resourceful British operative. On the day after a bombing raid over London, Sally is involved in a grim act that sets the tone for the mission ahead: she signals the enemy planes, and in the chaos that follows she is somehow connected to the murder of an innocent man in his home. The next morning, Sally boards a passenger liner bound for Canada, stepping into a web of doubles and deception as she moves to fulfill a covert assignment that will test her loyalty and nerve.
Across the ship’s deck, two unlikely strangers take notice: Richard Greene as Jim Garrick, a British intelligence officer, and Albert Lieven as Jan Orlock, a Polish officer with his own hidden agenda. Jim is quickly recognized as a man on a dangerous mission, while Jan radiates a quiet confidence that draws Sally in despite her outward Nazi sympathies. Sally’s interaction with Jim is tense and wary; she rebuffs his obvious interest, but she welcomes Jan’s more discreet attentions as the voyage unfolds. Beneath Sally’s calm surface lies a precise, dangerous intent: she is a deep cover agent, shadowing Jan to uncover the Nazi cabal that surrounds him.
The voyage takes a cruel twist when the German heavy cruiser Prinz Eugen appears off the Atlantic, halting the ship with a boarding party that takes Jim prisoner. The captain and the crew watch in stunned bewilderment as the Germans survey the scene, only to let the liner go on its way. In a startling turn, it becomes clear that the Germans have captured an impostor; Jim re-emerges from hiding, exposing the ruse and complicating Sally’s carefully staged performance. This incident foreshadows a larger plot at work and deepens the intrigue aboard a ship that has become a floating chessboard.
Arriving in Halifax, Nova Scotia, Jan introduces Sally to his mother, Madame Orlock. The public image of the invalid matriarch is undercut by Jim’s manipulations, which he uses to craft Sally’s persona as a sincere Nazi sympathizer. The plan is delicate and dangerous: Canadian authorities are coaxed into recognizing Sally’s supposed loyalty, while the Orlocks and their allies maneuver to keep her close, all the while maintaining the illusion that she is a genuine convert to their cause. Sally’s cover is repeatedly tested as she feigns reluctance to pursue her relationship with Jan, hoping to shield Jan’s true allies and learn their secrets from within.
As the layers peel back, Jan reveals his own precarious position within the conspirators, confessing a recent failure to disrupt a royal-bombing operation that relied on a misdirected signal. This confession begins to illuminate Sally’s earlier actions, including the moment when she killed a Nazi agent and inadvertently thwarted that ill-fated mission. Sally’s realization that Jim is not simply a passerby but someone assigned to her safety intensifies the tension; she discovers Jim’s presence in Jan’s study as he searches for incriminating evidence, and the two become unexpectedly aligned by necessity as the danger closes in.
When Orlock herself slips into Sally’s room, a dangerous moment nearly ends in tragedy. Sally quickly frames her defense as a ruse to mislead the enemy, managing to avoid capture. She then slips Jim a lipstick-note that instructs him to await directions at headquarters, a small act of collaboration that raises the stakes even higher. With Orlock pressing Sally to confide her true loyalties, Sally deflects and resolves to warn Jim through a rapid, covert exchange of information. The chilling logic of the spy ring comes into view: the leader’s network stretches through the hotel’s guests and even reaches a port immigration officer, binding many strangers into a single, perilous operation designed to derail a vital convoy.
Orlock’s plan hinges on deception and timing. Sally is ordered to telephone Jim and announce a fresh attempt to sabotage the Queen Mary, which is due to sail that night. The race to stop the plot unleashes a wave of countermeasures: RCMP officers are dispatched to the Orlock residence, Royal Canadian Air Force bombers are dispatched to neutralize the threat, and naval intelligence coordinates to thwart the sabotage from within. The momentum of the investigation shifts dramatically when Jan, driven by a mix of guilt and loyalty, shoots Sally; the bullet is unexpectedly arrested by a cigarette case he had previously given her, a quiet symbol of a complicated past and a fragile trust that will complicate any hope for reconciliation.
In the end, Sally’s cover is blown, but not undone. The romance that has threaded through the danger culminates in a marriage between Sally and Jim, establishing a fragile alliance that transcends the deception that defined their voyage. The couple returns to London, where Sally’s double life has left its mark on her family and on the harsh lessons of espionage. The story leaves them standing at the edge of a postwar future, shaped by acts of courage, misdirection, and the costs of loyalty under fire.
- Sally Maitland, Anna Neagle — the undercover British agent whose calculated defiance drives the plot.
- Jim Garrick, Richard Greene — the British intelligence officer whose presence gradually reveals a deeper truth about Sally’s mission.
- Jan Orlock, Albert Lieven — the Polish officer who becomes both ally and obstacle in Sally’s undercover operation.
- Madame Orlock, Lucie Mannheim — the enigmatic mastermind behind the spy ring who orchestrates fear and subterfuge.
- Others from the cast contribute to the dense network of loyalties and betrayals that define this tense wartime thriller, each adding a layer of complexity to Sally and Jim’s improbable union.
