Mrs. Verloc (Sidney) and her husband Karl (Homolka) own a London cinema called the Bijou. Karl secretly works for a terrorist group on the side. Ted Spencer (Loder), the friendly employee of a produce market next to the Bijou, is actually an undercover detective for Scotland Yard, and has been tracking Karl's movements. Spencer has a chance to foil a bombing plot by the terrorists, but complications arise when the detective's cover is blown, and when Stevie (Desmond Tester), the young brother of Mrs. Verloc, gets mixed up in the plot.
Not to be confused with Hitchcock's later 1942 film Saboteur. For that matter, the novel this film is loosely based on, Joseph Conrad's The Secret Agent, should not be confused with Hitchcock's film Secret Agent, also released in 1936, but based on a story by W. Somerset Maugham.
This film features examples of:
- Adaptation Name Change: The first name of Verloc was changed from Adolf to Karl to avoid any Nazi connections.
- Anyone Can Die: Surprisingly invoked for a film of its era, as Stevie and Karl Verloc don't make it to the film's climax.
- Asshole Victim Mr.Verloc is stabbed and killed by Mrs. Verloc but he was working with the terrorist and played a hand in the death of Stevie and everyone on the bus. He also had been pretty insensitive about the fact Stevie had died because of him. All these factors don't exactly make him sympathetic when his ultimately killed.
- Big Blackout: The film begins with London going dark after losing all of its electricity, as it's revealed later, because sand was put in the boilers of London's electricity grid as an act of sabotage.
- Bittersweet Ending: The terrorist cell has been foiled, and Mrs. Verloc and Spencer are safe, but Stevie and Mr. Verloc are dead, along with dozens of others, and she's now a Karma Houdini, since Scotland Yard will never know that she killed her husband.
- Bomb-Throwing Anarchists: The terrorist gang, who resort to a planned series of attacks in London, though whether they are actually anarchists is unknown since their exact motives are not made clear.
- Dictionary Opening: The film starts with a close-up of a dictionary entry for "sabotage".
- Death of a Child: Karl asks Stevie, his wife's little brother, to deliver a film canister to the cloak room under Piccadilly Circus, but what Stevie doesn't know is that he's actually carrying the time bomb the terrorists asked Karl to carry. Stevie is delayed by several events, and the bomb explodes while Stevie is aboard a bus.
- Even Evil Has Loved Ones: A main thread of the story, as we see Karl Verloc try to maintain an image of being a loving husband and caring father figure to his young brother-in-law, even as he participates in despicable plots. The bird shop owner is also shown dealing with his wife and granddaughter.
- Even Evil Has Standards: Karl Verloc might accept to deliver bombs for a terrorist gang, but after they ask him to place a bomb at the Piccadilly Circus station, he objects that he is not comfortable with any act that would cause the loss of life (though that doesn't stop him from accepting the task, perhaps because at this point he can't).
- First Law of Tragicomedies: It starts off peppering the suspense with comedic bits, much like its Hitchcock predecessors The Man Who Knew Too Much and The 39 Steps, but it takes a very dark turn in the final act.
- Foreshadowing In the scene where Karl is talking to The professor about what he would do if he was ever caught by the police, the professor makes it clear he would kill himself with the bombs attached to him. At the climax of the movie that is exactly what happens..
- Internal Reveal: Spencer goes to Scotland Yard in an early scene, so the audience is aware that he's an undercover cop, but Verloc doesn't find out until much later, when one of his partners recognizes Spencer.
- Market-Based Title: Released as The Woman Alone in America in 1937, though its original title was eventually restored.
- Never My Fault: Verloc blames Scotland Yard and Spencer for Stevie's death rather than himself, saying that they were the ones who prevented him from carrying out the bomb delivery himself.
- Only in It for the Money: It is implied that Karl is with the terrorists not for sharing the same beliefs but because they pay him a pretty penny — after the London blackout affects the Verlocs' cinema and people demand their money back, Karl assuredly instructs his wife to return the money to the customers, despite her protests, because he has "some money coming in."
- Rewatch Bonus: In the blackout scene, Mrs. Verloc telling Spencer "If you don't go away I'll call the police!", unaware that he is the police.
- Ruritania: The gang of terrorists hail from an unnamed European country.
- Shout-Out: Hitchcock had been a big fan of Walt Disney's animated work, and Who Killed Cock Robin? plays at the Bijou in a key scene.
- Signature Style: An early example of Hitchcock using birds for sinister symbolism, as one of the members of the terrorist cell fronts as a bird shop owner.
- Spared by the Adaptation: Mrs. Verloc kills herself in the novel.
- Title Drop: Besides the Dictionary Opening, there's also the scene with the investigators at the power plant.First man: Sand!Second man: Sabotage!Third man: Wrecking!Fourth man: Deliberate!
- Ugly Guy, Hot Wife: With Oskar Homolka and Sylvia Sidney as the Verlocs, this trope applies (though you could say it's more like Menacing Guy, Pretty Wife).
- What the Hell Is That Accent?: Mrs. Verloc, played by New York native Sylvia Sidney, is specifically stated to be American, but Sidney plays the role with a Mid-Atlantic accent that blends in more easily with the other Brits in the story.