Figuring out what you want to be when you grow up sometimes requires that you first grow up. That’s true for the best of us and even for unblinking sociopaths like thirty-something Louis Bloom (Jake Gyllenhaal), who would have to earn a promotion to be regarded as a petty thief. He’s plenty smart and burning with single-minded ambition. He’s also a square peg in a world full of round holes — at least until he comes across a horrific one-car accident and the man filming it, Joe Loder (Bill Paxton).

Joe is a nightcrawler, a stringer with a police scanner and high-def video camera who spends his nights ambulance-chasing for footage he can sell to local television news outlets. You gotta be fast, you gotta be first, you gotta be shameless; most of all you better understand what the buyers are looking for: pictures of horrific things that happen to “good people.”

“Good people,” of course, means white and affluent.

It’s a perfect fit. Louis is already a creature of the night and unemployable. No one with half a brain would hire this gaunt, dead-eyed passive-aggressive con man who talks like he was raised on how-to-succeed-in-business cassettes from the 80’s. There are people in the world that if you let them get even one hook in you, it’s only going to end ugly. Louis is one of those people.

And so is Nina (Rene Russo) who, despite being gifted with Diane Sawyer’s sex appeal and smarts, has lived the career of a news editor forever treading water. Pushing 60, she’s now one sweeps week away from going under for good. Nina seems to believe she hasn’t been ruthless enough to succeed. Louis is her tool to remedy that.

In Louis and Nina you have what the true-crime folks call a Wicked Attraction. Without finding the other, Louis probably would’ve finally met the wrong rent-a-cop while stealing chain-link fence, and Nina most certainly was on track to become one of those aging never-weres who wear too much make-up and haunt every rundown apartment complex in Los Angeles. Together, though, their dark ambitions  feed one another, and God help anyone who gets in the way.

In these two characters, writer/director Dan Gilroy blisters the cynical and mercenary ethos of Los Angeles local news with the same blowtorch director Sidney Lumet and screenwriter Paddy Cheyefsky used against a fictional national television network in 1976, a network that looks less fictional with each passing year.

“Nightcrawler” also does something I absolutely love in movies: takes you on a grand tour of a subculture. Louis and Nina are (hopefully) exaggerated. Nonetheless, Gilroy’s story is grounded enough to capture the essence of what it must be like to hurry up and wait to profit on human tragedy in a gutter of a city.

Another bonus is how well Gilroy captures Los Angeles in all its steel-barred, stucco’d, paved, sprawled, smoggy, strip-malled one-story-ghetto glory. If you want to know how the real Los Angeles looks, feels, and smells — this is it. It is also good to see Rene Russo (Gilroy’s wife of 20 years) back on the screen in a role she knocks out of the park.

Although I’ve never been much of a Gyllenhaal fan, there’s no question this is a career performance. He’s so  good we constantly forget what Louis is capable of. We’re caught off guard as easily as his prey. Wrapped in a compelling story that puts you in a trance are numerous jaw-dropping moments where you witness a shrewd, charismatic amoral eccentric doing what needs to be done to get what he wants — especially from Nina.

“Nightcrawler” is a dark tale, a neo-noir with no interest in making anyone feel good.  Los Angeles is Hell and these are the demons who feed on one another. It’s also a fascinating character study about sleazy people in a sleazy world that thankfull, doesn’t wallow in sleaze. You’ll certainly feel uncomfortable, but only as a tourist not a participant.

John Nolte on Twitter @NolteNC