Some movies about the seedy underside of American suburbia use a lot of sunny skies and bright colors to serve as contrast to the film’s actual themes. Michael Cuesta’s compelling, disturbing “L.I.E.” takes the opposite route, using overcast skies and dreary sets to underline, not contrast, the dreadfulness being hinted at onscreen.

Unsettling but admirably discreet, “L.I.E.” is about childhood lost (or destroyed) and the heartbreaking pathos that results when adolescents are left to become adults on their own. L.I.E. stands for Long Island Expressway, Cuesta’s metaphor for danger and deceit. 15-year-old Howie Blitzer’s (Paul Franklin Dano) mother was killed on the highway not long ago, and his unethically wealthy businessman father Marty (Bruce Altman) has eased the pain by taking up with a nameless bimbo.

Marty’s not much of a father these days, but he’s not a bad person. His wife’s death knocked him for a loop, too, and while he wants to get to know his son better, he hasn’t had much practice at it. He literally sees the faces of his wife and young son in every room of his large, impersonal house.

Howie is left to fend for himself, going to school only occasionally (a fact which flusters Marty more than anything) and mostly hanging around with a cadre of semi-delinquent semi-juveniles, all of whom try to be older by smoking, swearing and having (or at least talking about) sex.

As often happens in the dynamics of adolescents boys’ friendships, Howie starts spending more time with Gary (Billy Kay) and less time with the other two kids. The four of them will break into houses, mostly just for kicks, and then split into two pairs and go their separate ways. Independently of the others, Gary and Howie one night break into the basement of Big John Harrigan (Brian Cox), a middle-aged pillar of the community who has too much shag carpeting and a set of personalized license plates that say “BJ.” Gary, we learn, has reasons for choosing this house: Big John’s got him in a sex-for-money operation, and this is his only course of revenge.

This detail goes a long way toward explaining Gary’s behavior toward Howie. He stands too close, asks personal questions, and wants him to join him in running away to California. Howie, meanwhile, says more than once that he’s not gay, and he’s probably right. However, missing his mother and lacking a strong male figure in his life, he’s trying on Mom’s lipstick and thinking too much about Gary … and, soon, about Big John.

Big John, who proves to be one of the oiliest, most horrible characters in a long history of movie pedophiles, attaches himself to Howie in a manner that will make you squirm. A scene in which he propositions the boy outright is almost unbearably creepy, and fantastically acted by Dano and Cox. Despite his motives, though, he also serves as a surrogate father. Left with nothing else, Howie almost has no choice but to take whatever good things Big John can offer him, while trying to avoid the bad.

Cuesta is a whiz with characters, palpably conveying emotion from every character, often through carefully placed details. Told by his more adult lover Scott (Walter Masterson) that he should be ashamed of himself, Big John says, “I am. I always am,” and we believe him — a moment of sympathy for a character largely undeserving of it. Gary swaggers when he walks, moving his small little body around like the grown-up he’s trying to be. Howie, for a similar effect, is always having to pull up his pants: He’s a kid trying to wear clothes that are too big for him, literally and figuratively.

There’s also a great sequence in which Howie and Gary have sneaked into each other’s bedrooms at the same time, looking for something. The film cuts back and forth between them, and we see more deft character touches: Gary’s house is unkempt and messy, his parents apparently gone as literally as Howie’s are figuratively. Both boys spontaneously know to look under the mattress for secret things. Gary takes off his shirt to look at himself in Howie’s large mirror.

Who would enjoy this movie? Well, I don’t know that it’s supposed to be “enjoyed,” in the traditional sense of the word. Anyone with an eye for well-made, well-acted, emotionally powerful films will certainly find it worth watching. Though a child molester is a main character, it should be noted that the movie is more about loss of innocence than about pedophilia specifically, and the end is far less depressing than it could have been. It’s a cathartic experience, and one that deserves to be watched — even if wincing causes you to close your eyes every now and then.

A (; R, abundant harsh profanity, abundant sexual dialogue and innuendo, some graphic sexuality, a little violence.)