It’s a summer AM in the middle of Pennsylvania Trump country, but Donnie is wearing his fur cap.

“It’s my work hat,” he explains, shrugging off the odd attire question.

His colleague in the garbage truck, Donna, is just grinding through another day. She hops back in the seat and Donnie just stares.

“You didn’t flip the lid down.”

That’s our second clue. A few minutes later, we see Donnie dig through a mountain of saved pens and magic markers — hundreds and hundreds of them. A character trait is underlined for us. Donnie’s “on the spectrum.” A little obsessive-compulsive, not quite picking up social signals, he’s one awkward conversation after another waiting to happen — squirrelly, maybe a little creepy.

Donnie is a most unusual character to serve as our tour guide to “A Dark Place.” British character actor Andrew Scott (“Spectre,””Pride” and TV’s Moriarty in “Sherlock”) utterly immerses himself in this “town weirdo” character who becomes obsessed with a little boy on his route who disappears, and then is found drowned in a local creek.

Director Simon Fellows (“Malice in Wonderland”), screenwriter Brendan Higgins and Scott have concocted an unsettling mashup of “Monk” meets “Gone Baby Gone” whodunit, a British production filmed in Georgia and awfully fond of showing all the “Trump” posters and yard signs in this corner of rural, Steelers-obsessed Pennsylvania.

Donnie’s back-story is layered, with no layer pointing towards him turning amateur sleuth when little Ryan Ziegler vanishes. Donnie drives a garbage truck because it’s the only work he can get, and his off-putting oddness makes you wonder if he should even be entrusted with that. He lives with his aged mother, collects sports memorabilia for his 11 year-old daughter (Christa Beth Campbell) who lives with her mother. The mom (Denise Gough) lets us see with just a glance how much she regrets every minute since a drunken one-night-stand with the town character.

Work partner Donna (Bronagh Waugh) shrugs off Donnie’s weirdness until he starts asking questions about the little boy who used to wave from the window of his parents’ house on Donnie’s route. She’s as shocked as we are at this turn.

What’s driving it? Did Donnie have something to do with the disappearance? He’s tactless enough to ask the grieving mom questions, and she’s not the first person whose social signals he misses. He hacks into his daughter’s Facebook and queries the missing boy’s foul-mouthed tweenage brother. The waitress at the diner (“Any strangers in here the past couple of days?”), the town’s lone detective (Griff Hurst), all get the Donnie third degree.

What the hell is up with him? The sheriff (Michael Rose) isn’t the only one wondering.

We scratch our heads, or maybe shake them at how implausible this garbage dump “Monk” is as a sleuth. But Donnie is used to poking through people’s trash. And he’s not an idiot. He just has problems with distractions, breaks in routine and questions left unanswered.

Scott makes a great tour guide, leading us down the rabbit hole of Donnie’s latest obsession. The plot includes confrontations and lines crossed that should land Donnie in jail, or dead. But something keeps those who might take drastic measures from pulling the trigger.

There’s always something or someone (Donna serves as a “Deus ex Donna” in this) who saves him.

Fellows immerses us in this world, focusing on the decay and despair in this corner of America where the “old mill” is long shuttered and the locals have been “left behind” by the rest of the country, underlining that with several images of Trump signs seemingly left over from the election.

Donnie, “A Dark Place” suggests, is that corner of America incarnate — off-putting, maybe creepy, uncertain in motive, but not someone we should discount, ignore or take for granted. He makes a most unusual big screen sleuth, and Scott’s unbalanced portrayal of him keeps us guessing what Donnie is thinking, what Donnie’s involvement in all this might be and most worryingly, what socially unacceptable, dangerous or extreme thing Donnie might do next.

MPAA Rating: unrated, violence, some of it committed on a child

Cast: Andrew Scott, Bronagh Waugh, Griff Furst, Michael Rose, Christa Beth Campbell and Denise Gough

Credits:Directed by Simon Fellows, script by Brendan Higgins. A Shout! Factory release.

Running time: 1:29