There are doubles everywhere in this film: doubled characters, opposites, mirror images, reversals, repetitions. It is a visual puzzle, and once you know what to look for, it’s a lot of fun, like a sinister maze. The leads, Joseph Cotten and Theresa Wright, as Uncle Charlie and his namesake, Young Charlie, carry the suspense between them — and never once let it down. They are perfect foils for each other.

There are parallel scenes: early on, in Philadelphia, the creepy Uncle Charlie looks out the window of a rundown boarding house on the edge of town. He faces a bleak landscape of vacant lots and rusting cars. At the corner stand two detectives. They are waiting for him.

Uncle Charlie is on the run, in need of shelter. He telegraphs his sister, Emma Newton, who lives in the idyllic town of Santa Rosa, California. He says he is coming for a visit on Thursday: “there’s no stopping me.”

We see him next in another upstairs bedroom, this one at his sister’s beautiful white clapboard house, shaded with a mighty oak. He is again looking out a window. Two ladies are chatting on the street corner, oblivious.

The film studies opposites. Innocence and experience; young and old; good and evil; life and death. Marriage and widowhood. Being inside a community, and being on the outside, an outcast. As these pairs run throughout the story, they threaten to run into each other.

At the center of the story are the doubts of a young woman — at one point she calls herself “a cranky old maid;” she can’t be more than 20 — confronting adult life. For a young woman in 1942, that means marriage.

She studies her mother, whom she sees as buried in an endless routine of shopping, cooking, doing the dishes, and going to bed. Her father doesn’t do much better: he’s always at work. When he’s home, he reads magazines with titles like Unsolved Crimes and Mystery Murder for fun. It reminds of all those people who enjoy “true crime” podcasts, the genre of “strange but true.” To Young Charlie, the world, or adulthood, is at once empty, and menacing.

She reveres her uncle — yet he represents the dark inverse of everything a young woman might want. He gives her a ring, a symbol of his love for her. Not only is it stolen, it was taken from one of three women he has strangled to death. He is a fugitive serial killer known as the Merry Widow murderer. He seduces rich, independent women — and then does away with them.

Thornton Wilder wrote the film in 1942, during his five last weeks before he was due to join the American war effort in Europe. The world had become a threatening and dangerous place. Reassuring backdrops, like that of the American small town, suddenly seemed not so much fraudulent as terribly vulnerable. An establishing shot that reveals Santa Rosa to the viewer is centered, not on a church spire, as in It’s a Wonderful Life, or a tolling bell, another stock image of small town order — but on the Bank of America. In the thirties, all banks did was fail.

While the film tries to steer a course between the menacing and the routine, it cannot seem to keep to it. Its darkness, in the form of Uncle Charlie’s irrational hostility, threatens to overwhelm the everyday.

That is because that darkness finds its counterpart in Young Charlie’s “nervyness” — what we might call anxiety. She’s “high strung,” says her father. “It’s on account of her intelligence.”

She figures out almost immediately that all is not right with Uncle Charlie. Her innocent joy in his arrival, her faith in his maturity and goodness, her admiration of the sophistication and urbanity he represents — all the things she wants for herself — are doomed by her own luminous intelligence. The film suggests that Uncle Charlie represents only an extreme version of the darkness of human life.  

A New York Times review of 1943 has one complaint: that the film’s moral “is either anti-social, or, at best, obscure.” I suspect that today, its darkness will be far more visible, and far more familiar.

Shadow of a Doubt screens at The Regent on Monday 3 March at 7pm. Join the Books on Film club, or just buy a ticket to the film at The Regent.