Trapped, a film noir produced in 1949, does a really nifty job of keeping you guessing in several ways. Lloyd Bridges gets top billing, so its safe to assume he's the hero--or (since this is film noir) perhaps an anti-hero.
But he's actually the main villain, without any traits that bring him sympathy. Heck, there's never even any real reason to think he's very good at being a crook.
Someone is passing fake $20 bills and the Feds realize they were made with the same plates that Tris Stewart had once used. Stewart is now doing a 7-year stretch for that crime. He's offered a deal--time off if he tells them where the plates are. At first, he refuses. Then, while on a bus being transferred to another prison, he has a chance to make a break for it.
But this is the first of several twists. The escape is rigged, because he has agreed to help the Secret Service track down the plates. But then he beats the snot out of the agent assigned to him and makes a break for it, determined to get the plates for himself. After making us think that maybe we were going to get a story about a man who redeems himself, we are simply given a rotten thug.
That's fine, though, because Lloyd Bridges is a fine actor and brings a nice balance to the role. Stewart is more mean that smart, but he's just smart enough to stay ahead of the Feds for a short time.
For a very short time, actually. He looks up his old girlfriend, but the Feds already have her apartment bugged and have an agent frequenting the club she works at as a cigarette girl. That agent makes plays for her and flashes wads of cash, setting himself up as a potential source of money for Stewart.
Stewart, by the way, does not know where the counterfeit plates are at first, but after roughing up his former (and now perpetually drunk) partner, he gets a line on them. He contacts the guy who now has them and expresses an interest in buying his way back into the funny money business.
That's where the undercover agent comes in. The Feds don't want to arrest Stewart until he leads them to the plates, so the agent has to worm his way into the deal with promises of front money. But if he blows his cover, there's no doubt that Stewart will kill him.
The agent is played by John Hoyt. Trekkies will remember him as the Enterprise's doctor in the original pilot episode "The Cage," but he has a long and varied career as a character actor. I don't remember many times where he got to play a tough-guy hero, so its fun to see him in this movie.
Trapped is in the public domain, so its easily available to find online. Or you could just let me do it for you: