It’s the way many a Western legend begins — a boy recognizing a somewhat older boy, a famous outlaw.

“You’re…you’re Billy the KID! I read about you in the paper!”

“Lies, mostly,” the kid will drawl — hard and impulsive and wise beyond his years, thanks to a life by the gun, on the run.

Thus does “The Kid” come to life, a dusty, blood-stained Western built on gritty performances of archetypal characters, flinty dialogue and just a dash of sentiment.

Veteran character actor Vincent D’Onofrio steps behind the camera for this fictionalized account of the last days of Billy the Kid, when his “nasty, brutish and short” life crossed paths with another kid whose life was blood-stained before he ever met William Bonney, and only gained purpose thanks to his time in the presence of the West’s most infamous outlaw.

D’Onofrio takes a small, pivotal role in his film, and delivers his customary fair value in the part — that of a sheriff hellbent on leading Billy to a lynch mob’s noose. But the actor turned director’s real gift here was calling in favors among the acting community, casting well and sometimes against type and knowing a tight script (by Andrew Lanham ) when he sees one.

Newcomer Jake Schur is the “other kid” in this tale — Rio, a farmboy whose efforts to save his mother from his murderously abusive father don’t save her. But at least the dead man won’t be coming after Rio’s sister, Sara (Leila George), or him.

That doesn’t take into account the dead man’s sadistic, unforgiving brother (Chris Pratt), a neighbor who storms in to take his revenge on the 14 year-old boy and his older sister. Only a handy knife and even handier shovel save them.

It’s when they’re on the run that they stumble into Billy the Kid’s New Mexico gang. But being around Billy means the law can’t be far behind. And Sheriff Pat Garrett (Ethan Hawke), two weeks on the job, knows where to find his man.

As Billy, Dane DeHaan has perhaps his first “perfect” role, all smudged and peach-fuzzed, yellow-teeth and a worldly growl that belies the character’s 22 years. DeHaan finally shakes off that “Leonardo DiCaprio Lite” label slapped on him in his youth. He just turned 35 and has darkened into the man who can play the “Kid” — manipulative and self-martyred, sentimental and utterly ruthless –aged beyond his years.

If you know your Western history, you’ll remember Billy and his captor Pat had history back in the Lincoln County War. So there’s residual respect, a desire to bring the outlaw to justice and not shoot him to death — with the rest of his gang, and two teens that they just met.

Hawke’s Garrett is classic Western cool — a confident gunman who doesn’t interrupt his shave as the stand-off begins, but rides in to cut off Billy’s last chance of escape.

“You shot a goddamned horse, Pat. Who DOES that?”

It is during the trek to trial that Rio bonds with Billy, who knows his secret and sees it as something they had in common. Billy’s first violence came when he was all of 13.

Garrett, “my own specially assigned sheriff,” is less sympathetic.

“You murdered men.” Ah, but Billy’s famous, even if the newspapers print “lies, mostly,” he tells the boy.

“You know what it means when they start writin’ about ya?” Garrett adds “It means you’re already dead.”

The story beats –shootouts and attempted escapes — are timeworn, but screenwriter Lanham (“The Shack, “The Glass Castle”) concocts the occasion good line and the cast and director make them work.

“I hope you’ll rightly understand I had to at least try,” Billy apologizes after one failed attempt. He may have squandered his “last chance at decency,” to Garrett. But he has his reasons. Nature and nurture did him in.

“Ain’t no good moment I ever had weren’t a lie.”

The bonding scenes have the odd tin-eared line. One of Billy’s speeches plays like, well, a speech. The picture falters in the late acts before rallying for the only finale you can imagine, given the circumstances.

Hawke is on his game now. Ignore his Oscar-worthy “First Reformed” performance if you want. Watch him bellow his way around a lynch mob as Garrett and you’re seeing the definition of a “star turn,” focused, resolute and not given to sentiment when it comes to violence — larger than life, right down to the way he wears his hat.

But I cannot get over how satisfying it is to see Chris Pratt as the heavy. The sadism fits better than the (fake-ish) beard. If Westerns are to be believed, the lawless just-closing frontier was filled with murderous misfits like this guy — bullies whose violence was generally aimed at the weak, whose bravado was wholly based on how they stood up when faced with a “genuine celebrity” in the rough justice of a “count to ten” duel on main street. Pratt makes him feel real, without his usual wink at the camera.

“The Kid” isn’t a perfect Western, but D’Onofrio briskly walks his mostly-on-the-money cast through its classic plot, tropes and archetypes. Who knew Brooklyn’s own Mr. “Law & Order” was a fan? I only see one horse opera (“The Magnificent Seven”) in his acting credits. “The Kid” shows us he’s a lot more at home in the genre than most any of his co-stars in that one. And that he took notes.

MPAA Rating: R for violence and language

Cast: Ethan Hawke, Chris Pratt, Dane DeHaan, Leila George

Credits:Directed by Vincent D’Onofrio, script by Andrew Lanham. A Lionsgate release.

Running time: 1:44