An angry, antisocial inmate. An angry, unbroken horse. A program to have prisoners train wild mustangs to be sold at auction, rather than euthanized. You know where The Mustang is going.

Except you don’t, really. The movie, from Belgian actress-turned-director Laure de Clermont-Tonnerre, takes some unexpected turns and either minimizes or rethinks a lot of the expected man-beast bonding points. For a first feature, it’s also a remarkably assured and visually creative work.

The anchor is Belgian actor Matthias Schoenaerts (Far From the Madding Crowd), whose European glamour disappears behind the gritty, taciturn and quintessentially American face of Roman Coleman, a prisoner whose story is revealed only gradually. It’s a fine, restrained performance that minimizes emotional outbursts and thereby makes those moments the more powerful. (Schoenaerts can now be forgiven for Red Sparrow.)

Also on hand is Bruce Dern, doing his crusty curmudgeon thing as the head of the horse training program; Jason Mitchell (Straight Outta Compton), as a fellow inmate/trainer who’s the movie’s only upbeat character; and Gideon Adlon (Blockers) as Roman’s reluctant and only visitor. The rest of the supporting cast could be actors or actual prisoners from the Nevada State Prison where the movie was filmed — they’re impressively indistinguishable.

Rote subplots about drug-running and white supremacy in the prison are not as smartly developed as the main story line, but they provide necessary structural elements to the screenplay (by de Clermont-Tonnerre and two collaborators). One “anger management” session with the inmates, including Roman, is especially revealing for anyone who tends to dismiss convicts as bad seeds.

The movie has an agenda, beginning and ending with title cards about the actual mustang training program that inspired it, but it plays as a deeply human drama, not propaganda. Deeply equine too, for that matter.

Grade: B. Rated R. Showing at Grail Moviehouse and Flat Rock Cinema.

(Photo: Focus Features)