A man of violence who throws in his lot to protect the defenseless was a movie trope long before Brandon de Wilde yelled “SHANE! Come back!”

So let’s see how it fares in “Boon,” with veteran heavy Neal McDonough (“Walking Tall,” TV’s “Van Helsing”) playing Mr. “A History of Violence,” a hit-man on the lam who helps those once who helped him.

McDonough co-scripted this contrived star vehicle, a thriller that lets you see all the wheels arbitrarily set in motion and hear every gear that grinds along the way.

“Nick” is a wanted man, making his way to the border between Washington state and Canada. A Fed named Redd (Demetrius Grosse) is on his tail. But he’s playing catchup. There’s already somebody trying to silence this hired killer. But this guy (“Dragon” star Jason Scott Lee in a single scene) doesn’t even have time to fit his silencer on his pistol before Nick has the drop on him.

Wounded in the shootout, Nick stumbles through the woods and wakes up in the care of a widowed preacher (Christiane Seidel of TV’s “The Queen’s Gambit” and “Godless”) and her teen son (Jake Melrose).

She shares a bit of her story, but Nick is cagey and silent, which won’t fly with her.

“I think it’s only right that you tell me how you were shot” and ended up on her land.

Nick gets well enough to head off to a rental and extract the bullet himself (sure), but Catherine the pastor has other issues, which Nick figures out soon enough. She’s obligated to some seriously lethal scumbags who are “doing some work on our land.” Nick figures out what that might be, the “blind eye” she’s turning, and what her and her son’s fate will be once Fitzgerald (Tommy Flanagan) and his crew have no more use for them.

“Boon” does a terrible job of saying why the Baptist preacher is going along with these goons’ plans. It introduces her as a Good Samaritan owed a favor and mentions Nick’s Catholicism, as if any Catholic not “In Bruges” would be confessing his sins in BFE, Washington.

But all this script is concerned with is facilitating the characters moving from one violent encounter to another. Nick is handy with any firearm you can name, and when the chips are down and the odds are at their highest, he might just improvise.

Hey Nick, whatcha gonna do with that SPOON you just plucked out the kid’s cereal?

There are goonish henchmen and Fitzgerald’s vengeful Olivia Wilde-look-alike daughter-in-law (Spanish actress Christina Ochoa) also to contend with. And let’s not forget our lone Fed, on the clock and inexplicably by himself.

There’s more care put into bodies being yanked backward by a shotgun blast, and in McDonough’s fedora and turtle-neck hitman attire, than in any scene or exchange of dialogue in the script, co-written by director Derek Presley, McDonough’s co-conspirator for the little-seen 2021 Neal-as-hitman thriller “Red Stone.”

The big shootout is big enough, but is there enough leading up to it to make us suspend disbelief, invest in characters and care? I think not.

Rating: unrated, graphic violence, drug abuse, profanity

Cast: Neal McDonough, Christiane Seidel, Demetrius Grosse, Christina Ochoa, Jake Melrose, Jason Scott Lee and Tommy Flanagan.

Credits: Directed by Derek Presley, scripted by Neal McDonough and Derek Presley. A Cinedigm release.

Running time: 1:35