Detour follows Al, a piano player in New York who decides to sell everything he owns and hitchhike to Los Angeles to be with the woman he loves. After a period of time(days? weeks?) he's picked up by a man who happens to be heading all the way to LA. A gambler by profession, the driver is talkative and friendly, buys Al lunch at a diner, and allows him to drive part of the way so they can sleep in shifts and arrive that much faster. When the driver dies of a heart attack, Al is convinced the police will blame him for the murder no matter what he says, so he buries the body and assumes the man's identity. His plan is to ditch the car once he gets to LA and can disappear into the city. Stopping for gas, he picks up a hitchhiker, Vera, who unfortunately for him happens to be the one person on this stretch of highway that knows Al isn't who he says he is. Vera assumes Al has killed the driver for the several hundred bucks he had on him, and proceeds to keep Al on a very short leash, taking most of the money and scheming to get more.
Detour makes a good piece of evidence for my previously stated theory that noir films take place in their own parallel, tightly contained universe. It also makes a good contrast with Dark Passage, which is similarly obsessed with travel. But where Dark Passage displayed travel out of the purgatory of noir, Detour is very much about falling into that doomed arena. From the opening credits this is made clear, as the credits roll over a shot of highway stretching out before us. A car is racing down the highway, but our view is from the rear, so we see the highway disappear behind us. We're moving away from something, or towards Noir Country. Detour is all about how on man can make the wrong turn and wind up trapped in the fatalistic web of noir, with it's fog filled streets, canted angles, harsh, suspicious shadows and untrustworthy dames. Detour depicts a man's fall from grace, and even Al himself refers to his previous life as 'heaven'. Now Al is stuck in a world where the lights dim as he tells his story, coming to a pinpoint focus on his eyes. A world where all the cars seem to be travelling the wrong way down the road(a result of flipped negatives). The world of Detour is a world where something is fundamentally wrong, and Al represents the man who got lost on his way past, and is now stuck due to the vagaries of fate.
But is that really true? Is Al a blameless victim of circumstance? Surely that's what he'd like us to believe, and what we see on screen backs up that claim. But then again, what we're seeing is what he's telling us, and his story seems a bit too convenient. A bit too forgiving of a man who could. in the end, be held responsible for two murders. Did the driver really die of a heart attack, or did Al simply frame it that way to make his theft more understandable? Surely even in an allegorical film noir the evidence would show Al hadn't murdered the man through coronary thrombosis. And what about Vera? There's something about her unpleasantness that seems heightened. Her dialogue seems overwritten in a manner unlike anyone else in the film. It strikes me as a drastic rewrite on the part of Al's memory. Why would Al stay with Vera through this unless he initially wanted to? Even a character as spineless as Al would be able to see her threats were hollow, and her plans impossible. And surely her end is one of the more implausible cases of accidental homicide the screen has ever seen. There are two ways to read this; either Al committed those murders intentionally, or he was simply happy to do nothing to prevent them and reap the benefits.
Detour reminds me of an extended Tales From the Crypt or Twilight Zone episode. A story where the main characters tries to present himself as sympathetic but is truly just a heartless opportunist, and pays for his crimes with a harshly ironic punishment. Sure, the cops show up by the end, but the real punishment here is that Al has been sentenced to a living hell. He's left behind the sunny vibrant world of the living and exists in a sweaty, smoky, eternal night. He's entered Noir Country.