In the latest release from British writer-director Andrew Haigh (“45 Years,” “Weekend”), adapted from the 2010 novel by Willy Vlautin, Charlie Plummer is Charley, a weedy 15-year old being nominally raised by an impetuous father, Ray (Travis Fimmel). Ray and Charley get along, but Charley's expectations of home life are low. Bacon and eggs cooked by a woman who spent the night with his dad is an unexpected treat. (Later, this dalliance will separate father and son in a grisly but not unexpected way.)
For Ray's new job they’ve moved into a run-down rental in the outskirts of Portland, Oregon. It's running distance from the horse track Portland Meadows where Charley, training for a spot on his new hometown's football team, chances on a job looking after worn-out American quarter horses for gruff trainer Del (Steve Buscemi). They're soon joined on the fair circuit by jockey Bonnie (Chloë Sevigny), who can make Del see the absurdity of railing against competitors who accuse him of cheating just mere minutes after doing just that—their only way to win. She also advises Charley not to get too attached to the horses. "They're not pets," she warns.
Enter Lean on Pete, or Pete, as he's called, a five-year old run into the ground by Del and bound for a slaughterhouse in Mexico. Unhinged by a recent life-upending event, Charley takes off across eastern Oregon in Del's truck with Pete in the trailer hitched to the back. Charley has a vague notion of finding a long-lost aunt in Wyoming, but his more pressing concern is staying out of range of any adult who could impede their freedom. Charley hasn't just gone feral; he's wild.
As his films attest, Haigh understands desperate isolation. Especially amongst other people, his characters are uncomfortable or agitated, looking for an answer or somewhere to belong. Charley is no exception. Any assistance he receives, whether it's from Del or Bonnie, the rural videogame-playing roughnecks or an addict living in an RV (Steve Zahn), is bristling with menace. His one solace, pouring his heart out to Pete as they make their way across the desert, inevitably ends in grief.
So why, other than sadistic voyeurism, should viewers put themselves through these travails with Charley? For all its grimness, the film also depicts moments of pure joy, if only as relief. In one scene, a waitress convinces her manager to let Charley go after an attempt at a dine and dash; not out of the goodness of her heart but because a bus of tourists has just arrived and the kitchen is slammed. Still, Charley never fails to be grateful.