It's a concept that could've gone either way: Stick Tom Hardy, one of the most dynamic actors in cinema today, in the front seat of a car for the full length of a movie, forcing him to act, pretty much, just with his face. Locke unspools in something close to real time as a construction foreman named Ivan Locke (Hardy) drives to London in the middle of the night to deal with a crisis, causing his life to fall to pieces in the process. The only other people in the film appear on the car's speakerphone, and Hardy, an actor who can demonstrate a whole hell of a lot of swagger when he wants to, plays Locke as a reserved, intelligent man who doesn't offer very much of himself to the people he's calling, or to the audience. There's no overacting here, no gnawing on the steering wheel, and—what do you know?—the quiet approach was the right way to go.

Locke is an intense filmgoing experience, mostly because it bristles with the high-wire intensity of a really intimate one-man show—in fact, it's actually even more powerful than most dramatic monologues because we spend most of the movie practically sitting in the actor's lap. Director Steven Knight, working from his own script, uses the world outside Locke's car to demonstrate his interior life: When things are getting stressful, police cars streak by, sirens blaring, on their way to an accident scene that we'll never see. When Locke feels alone and detached from everyone he's calling, the roads seem empty and he might as well be driving his truck in outer space. It's a great gimmick that never feels overdone or cheesy.

I don't want to get too much into the specifics of Locke's situation—part of the pleasure of the film involves getting to know Locke through his predicament—but Knight's script fleshes out the character by focusing on his devotion to his job. Locke has fled town on the eve of the most important day of his professional life; he was to oversee the laying of the largest concrete foundation in European history, and you learn that he's a man who takes a lot of pride in a job well done. He's running from responsibility and running to responsibility and trying to make everything right, to fix an unfixable situation, and to be a good man while he's doing it. ("I want to find a practical next step," he pleads to one of the many distraught people he's calling, but he seems to be the only one who does.) He describes concrete with the dedication and the passion of a skilled lover. Coworkers who take pride in their work become brothers-in-arms, and incompetent coworkers are beneath contempt. For Locke to abandon his job, you quickly realize, means he must be facing some kind of personal apocalypse. Those aren't just cracks in his composure—they're howling chasms.

At its best, Knight's script flows like the very best of David Mamet. At its worst, it gets a bit too theatrical for its own good, especially in scenes where Locke addresses a phantom passenger in the car, giving his inward-leaning character a few broad, stagey moments to strut in a manner that betrays everything we've learned about him previously. But for most of Locke's taut 85 minutes, we get to watch an excellent actor transform a unique script into a memorable, admirable performance. It's a movie that feels entirely assembled out of indomitable will, and that's a rare and beautiful thing to see.