As "Little Children" begins, the tranquility of the upper-class suburban town of Wyndam, Mass., has been disturbed. A skinny, middle-aged pedophile has moved into the neighborhood, fresh out of a two-year prison stint for exposing himself to little boys. Already, the town's parents are posting fliers on telephone poles, warning their neighbors about the man's presence.

But this isn't a movie about sexual predators. The little children of the title are involved only tangentially, mostly as a way of connecting the adults to each other. The irony, missed by all of Wyndam's anxious, indignant citizens, is that the ex-con doesn't pose nearly as great a threat to their peace of mind as their other neighbors do.

This is the second feature from "In the Bedroom" director Todd Fields, and it's a markedly more satiric, more visually interesting affair than the somber (but spectacularly well-acted) downer that "In the Bedroom" was. The way Fields tells this story, which he adapted with Tom Perrotta from Perrotta's book, is unflaggingly engaging, like a novel that gets more audacious with each chapter.

The most noticeably unusual feature is the film's use of a narrator who is not also a character in the story. With the authoritative, detached, and slightly wry voice of Will Lyman (who voices PBS's "Frontline" series), the narrator is omniscient, and the film surprises us by constantly expanding the story to include new characters, always introduced and explained in Lyman's comforting tones.

We first meet a bevy of housewives who gather at the park every morning with their children. Three of them are more or less interchangeable; the fourth, Sarah Pierce (Kate Winslet), is different from them, and all four know it. Sarah, the wife of a workaholic husband and mother of an adorable little girl, isn't as pristinely efficient as her robotic counterparts. Sometimes she forgets to bring a snack for young Lucy. She feels unfulfilled, something her fellow moms can't relate to, or at least not that they could admit.

The other three giggle and swoon over Brad (Patrick Wilson), a handsome househusband they've dubbed "Prom King" who occasionally visits the same park with his little boy. They've never spoken to him, a fact that encourages Sarah to finally break the ice and prove she's different from these silly-minded housewives. Brad and Sarah start a friendship together, ostensibly so their kids can play, but really because they enjoy one another's daytime company.

Brad's wife, Kathy (Jennifer Connelly), is supportive but emotionally cold. She sends him out to the library every night so he can study for the bar exam (he's already failed it twice). Every night on his way to the library he passes a skate park where teenage boys spend hours perfecting their skateboard tricks, and he winds up stopping to watch them instead of studying. There is nothing untoward or sexual in his admiration of them; it's his own youth he's recalling. These guys are the age he was when he was a football hero, young and virile and full of potential. He was so happy then. What happened?

Brad and Sarah's friendship goes further than it ought to, and one of the film's minor disappointments is how predictable that is, and that is happens for the usual reasons: their spouses are distant, they don't understand them, etc., etc. (The other minor disappointment is the use of the old trope where characters read a novel -- in this case "Madame Bovary" -- that parallels their lives. Don't people in movies ever read books that have nothing to do with anything?)

While Sarah and Brad are the main focus, we also learn the stories, sad, funny, or both, of their friends and neighbors. That includes some scenes with the pedophile, Ronnie (Jackie Earle Haley), whose aged mother (Phyllis Somerville) thinks he's a good boy who just needs a girlfriend to help settle him down. They are constantly harassed by Larry (Noah Emmerich), an acquaintance of Brad's who has made it his duty to make life a living hell for Ronnie and his mom.

Fields has grown as a director since his auspicious debut film. "Little Children" is superbly handled all the way through, but one scene sticks out in particular. In the midst of a heat wave, parents have their children at a public pool when Ronnie the sicko suddenly shows up to take a dip. Fields gives the scene the full "Jaws" treatment (without the music), using little dialogue and only a perverse, subtle sense of humor to make the sequence look like a shark attack.

The point, ultimately, seems to be that dangers, both physical and emotional, lurk everywhere. Presenting sunny suburbia as having a dark side is not a new tactic, of course, but Fields and company present this grim, smirking fable with refreshing ingenuity. It combines sardonic humor with a piercing glance at the soul-crushing blandness of daily life.

Grade: B+

Rated R, some very strong sexuality and nudity, scattered harsh profanity, brief violence

2 hrs., 17 min.