‘WHITE BOY RICK’

R 1:50

It’s easy to see why someone would want to make a movie about Ricky Wershe Jr. His life story, the inspiration for the new, fact-based crime drama “White Boy Rick,” has it all: drugs, sex and gunrunning, plus a main character whose neck-deep involvement in all those activities — while still a teenager — is both shocking and appealingly guileless.

It’s a little bit harder to explain why you should watch such a depressing, and at times even soul-sucking, movie.

Set in 1980s Detroit, at the height of the city’s crack epidemic, “White Boy Rick” is permeated by an atmosphere of grimy hopelessness that makes it hard to watch.

Ricky’s old man (Matthew McConaughey), sells modified AK-47s, with the help of his son, to drug dealers and other shady customers. The threat of prosecution by the FBI is used as leverage to lure Ricky (played by babyfaced Baltimore newcomer Richie Merritt) to go undercover as a 14-year-old drug informant. This is where the film starts to get interesting — if also, let’s face it, something of a downer.

Taking its title from the nickname bestowed on the younger Wershe by some members of Detroit’s black underworld, “White Boy Rick” covers a span of only three to four years. Yet within that brief window, the film charts its adolescent antihero’s unlikely rise and predictable fall, from lawenforcement operative to outlaw, when agents (played by a maternal Jennifer Jason Leigh and a businesslike Rory Cochrane) cut Ricky loose from the informant program. After that, he uses the skills he learned as a fake drug dealer to become a real one.

At one point, Ricky is shot in the gut in retaliation by a rival, leading to him wear a colostomy bag. French director Yann Demange (“‘71”) doesn’t flinch about showing any of this, a frankness that the filmmaker turns into a kind of perverse stylistic asset when it comes to drawing our attention to the story’s most sordid details.

“White Boy Rick” is an engrossing-enough cautionary tale, if that’s what it is. But whether there’s any deeper meaning to a story that tries only halfheartedly to say something about the fragility of family is debatable. Still, the performances, which include cameos by Bruce Dern and Piper Laurie as Ricky’s grandparents, are all very good.

Starring: Matthew McConaughey, Richie Merritt, Bel Powley, and Jennifer Jason Leigh. (Crude language throughout, drug material, violence, some sexual references and brief nudity.)