Kansas City Confidential (1952)

A guy gathers himself a small crew to rob an armored car. He's got everything mapped out perfectly, right down to the florist who always arrives at the same time as the armored car. Wait for the florist to drive off, pull up immediately in an identical van, ambush the guards, speed off. Hide the van in a big truck while leaving the state and then make the crew scatter until it's safe to split up the dough.

So at first glance, it seems like a heist movie, but the heist itself was done within 10 minutes. Then it seems like it'll be the rest of the crew that blow it. There's a degenerate gambler with bad nerves (Jack Elam), a would-be Lothario (Lee van Cleef, weird to see him in a bright-colored hat), and a silent guy prone to violence. They always wore masks around each other, so only the mastermind knows exactly who's involved, but it seems like their flaws could tear it apart.

But that's not what this is, either. Because the driver (John Payne) of the real florist van took the fall, at least long enough to get repeatedly roughed up by the cops while in custody. The movie doesn't actually show the cops beating a person we know is innocent - probably violates the Hays Code - but we see Payne having to be helped along back to his cell and basically collapsing on the cot.

Eventually they find the other van (though of course one meathead cop insists he could still be involved), but the damage is done. Payne lost his job, his picture is front and center in the papers as an ex-con (something related to gambling) linked to a $1.2 million heist.

He gets a line on Elam's character via the brother of a war buddy, coincidentally about the point when the mastermind's calling everyone together. Elam doesn't survive the trip through customs, so Payne tries to pass himself off as Elam. So it becomes cat-and-mouse, as van Cleef and the other guy think Payne may be the other guy, but think there's something funny about him. The mastermind knows Payne isn't, but none of the three ex-cons know who he is.

The movie even adds another twist as to the mastermind's true goal in the last quarter of the movie. It mostly works, better than the mastermind's last-second change of heart, which is probably the only thing that keeps Payne out of the electric chair.