In 1945 Edgar G. Ulmer, whose three-decade career is comprised mainly of low-budget “B” movies, made a movie in a few weeks for The Producers Releasing Company, a low-tier Hollywood studio that, along with others of its ilk, was classified by its low-rent properties and lack of funds: poverty row. Within a couple of years of the release of Ulmer’s movie, a film-noir called Detour, PRC was defunct. Ulmer’s film ended up in the public domain, making it amazingly accessible, though usually only in poor quality prints.

Despite its humble beginnings and its bargain-bin fate, the film has made an impact and been recognized as an important, influential noir. The Library of Congress selected the film for preservation in 1992. The film has been lovingly restored in 4K, and The Criterion Collection released a home video edition of this 4K restoration this month.

It’s an unlikely candidate for such praise and attention. Its humble provenance and speedy creation rears its head throughout its short runtime (only 69 minutes). The principal actors were the relatively unknown Tom Neal and Ann Savage, and both remained relatively unknown — they are not great. There are several editing mishaps. The script, which utilizes a great deal of voice-over narration from Neal, beats us over the head. Roger Ebert’s review begins with this:

“Detour” is a movie so filled with imperfections that it would not earn the director a passing grade in film school.

And yet this review was written for Ebert’s Great Movies book, and he gives it four out of four stars. What is it about this flawed film that makes it a classic, then?

For all of its technical limitations and surface flaws, there is genius at work. It’s claustrophobic and muggy and, to me, unpredictable. Also, and most importantly for me, though the narrative is ham-fisted, Neal’s voice-over plays to the film’s greatest strength: the narrative might be one innocent man’s nightmare or it might be how that man was the nightmare for others.

As the film opens we meet our morose narrator, the star of this pathetic show, Tom Neal’s Al Roberts. Al sits in a small Reno diner, contemplating the unexpected road his life has taken.

Oh, he’s a sad sack!

And he’s easily agitated. Abrupt with those serving him, he also gets overly upset when a fellow patron of the diner goes to the jukebox and plays a song called “I Can’t Believe You Fell in Love with Me.” They try to calm him down and then, in that voice-over, Al starts to tell us, the audience, his story.

Turns out he was a piano player in New York City. The girl he loved, a singer who often sang “I Can’t Believe You Fell in Love with Me” while he accompanied, has moved to Los Angeles. When he realizes he wants to be with her, he decides to make his way, piece meal, across the country.

On this trip, however, he is forced to take a . . . detour!

While hitchhiking in the hot desert of Arizona, getting relatively close to his final destination, he seems to have a stroke of luck. A man pulls up in a nice car and offers to take him all the way to L.A. The man’s name is Charles Haskell Jr. He seems friendly, but it’s clear from the scratch marks on his arm that he’s been through something recently. He keeps asking Al to hand him a pill box and eventually he asks Al to take over the wheel so he can get some sleep.

I won’t go into much more here other than to say Al tells us an accident happened. We see it play out on screen, and yes it does appear to be an accident. Charles Haskell Jr. is no more. Afraid that he’ll be blamed for the death and potentially convicted of murder — I mean, Haskell is wealthy so it just makes sense — Al figures he’ll take the car into L.A. and ditch it. No one will ever have cause to approach him about an accidental death.

But for some reason — now gussied up in Haskell’s clothes, driving his car, spending his money, assuming his name — Al picks up his own hitchhiker.

This is Ann Savage’s Vera. The speaks tersely at the best of times, but when she confronts Al about Haskell’s death — she had been riding with Haskell already, she says — she stabs with every sentence. And Al is no match for Vera.

Afraid she’ll turn him into the police for Haskell’s death, Al gets sucked into Vera’s own schemes.

This detour gets worse and worse until, we know from the beginning of the film, there is no way for Al to get his life back on track.

The innocent man, wrecked by fate. And yet . . . Tom Neal’s Al is one of the most unsympathetic innocent men there is. Some of this is because Neal’s acting is one-note. But Al’s morose and self-pitying nature — he looks sad even when he’s playing the piano for the love of his life — plays out to great rewards: to him, life, has always been hard, even in the best of times. He’s the one who says: “Whichever way your turn, fate sticks out a foot to trip you.” This doesn’t seem to be a new discovery for Al; this is like his life philosophy.

Then again, going back to the fun of an unreliable narrator, Al is the narrator of this story. Our only narrator, in fact. His account of what happened before he blows up in the Reno diner might be meant to lull us in, to make us feel the pity he is trying to sop up. There may be more to this story than what we get. Al’s detour doesn’t have to be taken at face value. Al, after all, is a bit too self-pitying, a bit too showy in his sadness, a bit too submissive. Haskell is a bit too gluttonous for life, a bit too anxious for his pills. The lover waiting in California, the one who left Al once already, is a bit too giddy on her phone calls, a bit too pining for his arrival. And Vera is a bit too demented, her humanity a bit too . . . no, not “a bit too” — her humanity is completely absent.

The story doesn’t necessarily add up, making Al a bit too conflicted as the innocent man. Is all of this excess because the film was made in a few weeks, employing a group of actors that were just this side of being amateurs? Perhaps. But I don’t accept that. Though he made B movies, Ulmer was no amateur. He worked with some of cinema’s greats and knew how to work with what he was given. We are the beneficiaries here.