A wild, violent animal is tamed in “The Mustang.” But we’re not so sure whether it’s the horse or the man.

Laure de Clermont-Tonnerre’s understated and moving directorial debut is inspired by a real program in prisons in six Western U.S. states. Wild mustangs, which are on the verge of overpopulation, are rounded up on the countryside and taken to prisons, where inmates tame and train the horses to get them ready for auction. In a bit of a twist, it’s usually law enforcement agencies who buy the horses, using them for such purposes as patrolling the U.S./Mexico border.

Roman (Matthias Schoenaerts) seems part-animal himself when we first meet him, a heavily-muscled, nearly-mute inmate who has been transferred to a prison in northern Nevada. The viewer doesn’t learn what crime he’s in for until much later, but he's vibrating with anger and self-loathing for what he's done and who he is. When his estranged daughter (Gideon Adlon) shows up with emancipation papers, he signs them without a second thought, then barks “Don’t come back.”

But while on “outdoor maintenance” duty (shoveling manure from the stables), Roman finds himself strangely drawn to one of the horses, a particularly wild animal kept away from the others, kicking furiously at the walls of his stall. Roman knows how he feels. The program’s cantankerous head trainer (Bruce Dern, making a meal of a small role) sees his interest, and invites him into the ring with the animal.

Watching man and horse learn to overcome their rage and work together is quite poignant. In many scenes, Schoenarts is clearly right there next to the horse – no body doubles or camera trickery seems to be used – so the potential danger of the situation, as well as the bond that develops, is immediate and resonant.

Clermont-Torrerre and cinematographer Ruben Impens have an eye for finding lyrical images, sometimes in very un-lyrical places. “The Mustang” was shot in a decommissioned prison in northern Nevada, and is a deteriorating hellhole of concrete walls, peeling paint, and linoleum floors stained with dirt and blood. She captures some of the surreal imagery of everyday life in the prison, such as the visitation room, where inmates and their families pose for photos in front of a bizarrely cheerful backdrop of a sunny beach.

Outside, the landscape is almost as bleak, an unbroken brown vista of treeless fields and hills. It’s a pitiless place that reflects the emptiness in Roman’s soul, an emptiness that he slowly fills. Schoenaerts is a Flemish character actor (“Rust and Bone”) who may seem like an unlikely choice to star in a film like this, but he captures Roman’s rage, sorrow and eventual redemption with an unshowy realism.

A film that’s part gritty prison drama and part uplifting horse movie might seem like a strange mix, but “The Mustang” makes it work with authentic performances and a stark beauty.

Rob Thomas is the features editor and social media editor for the Capital Times, as well as its film critic. He joined the Cap Times in 1999 and has written about movies, music, food and books.