Spencer Tracy plays Tommy, a smart but arrogant young convict entering New York’s Sing Sing prison, where he’s set to serve five to thirty years for armed robbery. There, he clashes with the incorruptible warden, but time sees the two develop a mutual respect. A trust tested when the warden grants Tommy a twenty-four-hour leave to visit his ailing girlfriend, played by Bette Davis.

Lewis Lawes, then warden of Sing Sing, wrote the source novel, which explains Arthur Byron’s cigar-chomping warden’s pat characterization. In an early scene, one of Tommy’s entourage—played with an easy sleaze by Louis Calhern—attempts to bribe the warden with $5,000 in bonds. As Calhern explains how there’s “bales more where that came from,” the warden grins and sets the bonds alight with his desktop cigar lighter.

When Calhern balks at the refusal to play ball, the warden lays into him, saying Tommy will get no special treatment. “People on the outside are supposed to be created free and equal but they aren’t,” he says. ”In here, they are.” Suspect logic aside, the dialog crackles.

And it gets better. When the warden tries his moral reasoning with Tommy, it falls flat, with Tommy retorting, “Save that for Sunday warden, and let me pass the plate.” Good stuff.

The second act proves predictable. The warden confines Tommy to his cell when he refuses to work. Director Michael Curtiz mixes tight shots of Tommy with wide shots of the prisoners exiting their cells and marching with military precision. Tommy relents.

Then the obligatory prison break. The script helps by having Tommy recuse himself from the plan for superstitious reasons, thus leaving the escape’s outcome in doubt. Curtiz helps by cutting between the prisoners and the warden’s response. The result packs a surprising amount of tension.

But it’s Tracy who makes the movie. It’s easy to imagine George Raft or even Humphrey Bogart in the role, and the film floundering because of it. Tracy convinces as a brash but intelligent thug. He inhabits the role in a way his contemporaries hadn’t yet mastered. Later in the film, he’s on death row and when a fellow inmate starts his march to the chair, Tracy tells him, “Give my regards to Mike… and lookout you don’t catch cold.” It’s another hard-boiled line a lesser performer would have growled or emoted, but Tracy’s delivery conveys an unexpected pathos.

For her part, Davis begins the film as Tracey’s one-dimensional moll, but later sequences take advantage of her comparable talent. Her and Tracey’s final sequence together could have played as overwrought melodrama, but both inhabit their characters and recognize the camera’s immediacy. They underplay the scene to terrific effect.

Indeed, my one nit lies with Curtiz, who ends the film one shot too early. The film opens with Tracey entering the prison. It should have ended with him leaving.