Well...men can be so practical, sometimes.
I mean, he IS still in prison and all.
Joe Sullivan (Dennis O'Keefe) has a lot of time juice-stewing while in the slammer. He's taken the fall for the no-good-high-roller rat named Ricky Coyle (Raymond Burr) and ended up serving time and wasting it. His only high-points in the gray-bar hotel are when the do-gooder legal case-worker Ann Martin (Marsha Hunt) comes to visit him to try and get him out of jail if he'd just turn state's evidence. She's a cute kid and all ("Next time you come up, don't wear that perfume...it doesn't help a guy's good behavior"), but Joe's got other plans for busting out.
And that's where Pat Cameron (Claire Trevor), our narrator, comes in. She's been working angles outside, so that she and Joe can run away together, even if it is on the lam. Trouble is, Pat's a little on the desperate side and naive, and the plan that she's got for springing Joe comes straight from Ricky Coyle, who's having a very good time spending Joe's share of the loot and doesn't have any plans to split it. It doesn't occur to Pat that, should his prison-break succeed, it won't be just the cops they'll be running from, but Coyle's gang, as well.
But no one but Pat figures on Joe's resourcefulness and he does manage to escape...but just barely. A bullet-riddled gas tank from the attempt and "a dragnet tighter than a fist" forces them to start altering plans and Joe decides to hide out for a couple days at the one address that might hold a sympathetic soul, Ann's. Plan B is to take Ann hostage (for the police...and maybe for Joe) and meet up with Rick at Crescent City to settle scores. Joe and Rick have different ideas of what that means, and so he sends some hit-men to meet up with Joe and rid Rick of the problem for once and for all.
The triangulated action, between the pursuers and the pursued—who have their own internal tensions—makes it a more complicated plot than most noirs, despite the lack of mystery inside it. It's a standard chase, but coming at different angles, with the "wanted" man circled by two forces that want him dead or back in prison, and two women who want him alive, but with conflicting emotions about what that might entail. In the meantime, Mann never gives you a sense of space or of freedom. There's always a sense of entrapment from the dark frames of doors to the grill-work on the prison windows and everyday fences...right down to the veils that the women wear, even if it's a little premature to be in mourning. Still, in the noir-niverse, one can never start too early.