The Jack of the title is an awkward 15-year-old outcast living in New York’s Hudson Valley, in a run-down neighborhood that’s known and dismissed him since childhood. First seen nervously spray-painting an obscenity onto an enemy’s garage — a surprisingly belligerent act, given the predictable consequences — he doesn’t entirely lack courage or self-esteem. But he’s been beaten down by bullying, from his older brother Tom at home, and by local troublemaker Shane and his posse everywhere else. The town where they live seems insular and depressed, and without a car or a crew of his own, Jack is stuck inside a limited, claustrophobic territory. It’s impossible to escape Shane, or the schoolmates who know his weaknesses and triggers far too well.

It’s easy to forget how much a single terrific performance or a fresh directing perspective can enliven a film, and turn familiar ground into fresh new territory. On paper, Felix Thompson’s debut feature, the Tribeca Film Festival Audience Award-winner King Jack, looks like yet another small-town coming-of-age movie, one of thousands of cinematic stories about a troubled family and a kid’s first really hard life decision. But execution is everything. The film walks along well-established paths, and its story draws a simple, straightforward line from each character decision to the next logical outcome. But Thompson’s leads are so natural in their roles, and his filmmaking is so immediate and intimate, that King Jack is instantly absorbing. It’s artfully made, but sometimes its easy-flowing story and flawless naturalism makes it feel more like a documentary about teen life than a narrative film.

Things change for Jack when he's put in charge of his 12-year-old cousin Ben, who's visiting due to a family crisis at home. Jack's used to being given no leeway, freedom, or privacy at home, and briefly, he enjoys lording over the one person in his life with less social status. But his need for a friend rapidly overwhelms the novelty of superiority. Given someone to hang out with and show the small-town ropes, he briefly blossoms. Ben is just another potential victim and entertainment for Shane, though, and their conflict escalates rapidly. So much of King Jack lives in the actors' vulnerable, revealing faces. Charlie Plummer (Boardwalk Empire) as Jack gives the central role an understandable mixture of sullenness and neediness, a purely teenage blend of irrepressible hope and fear that someone will see it — and take cruel advantage. Plummer does wonders with the role just on his complicated facial expressions: he radiates caution, resentment, and eagerness at the same time. Whether he's facing a three-on-one beatdown or his first kiss, his darting eyes suggest he's weighing the possibility that he should be running to someplace safer. Cory Nichols as Ben projects a similar mixture of wariness and openness, but minus a few years of unpleasant life lessons; he's still ready to step into potentially humiliating situations, like a game of Truth or Dare with a couple of local girls, with the confidence that everything might turn out well. The two young actors have an entirely believable chemistry together, and as their characters cautiously bond, they evoke all the raw openness of the early teen years, when surface friendships form easily, without suggesting deeper trust.

The rest of the cast is just as suited to the material. Christian Madsen (Michael Madsen's son, looking startlingly like the young version of his father) as Tom gets few lines and little backstory, but the weight and banked violence he brings to the role suggests an entirely different, linked movie about a man trying to escape his own past and his dangerous habits. The girls in Jack's life — the precocious Robyn (Scarlet Lizbeth), a crush object who's flattered enough to string him along for amusement, and the sweeter Harriet (Yainis Ynoa), who sympathizes with him — both come across as coltish and just a little ahead of him on the maturity scale. And like Plummer, Lizbeth and Ynoa both find a balance point between diffidence and commitment, between awareness of their own power and a naïveté that excuses how they use it. The wistfulness comes in sharp contrast to the violence King Jack takes place over a couple of days in high summer, and it ably captures the endless freedom and weary boredom of kids wandering a town where, as Jack puts it, there's "fuck-all" to do. The adults in this story are all but absent, leaving the kids to find their own amusement in alcohol, their first awkward sexual fumblings, and above all, by experimenting with power dynamics at each others' expense. There's no real sense of era in this movie: Jack uses a cheap flip-phone to send awkward selfies to Robyn, but the internet seems like a myth, and so do weapons more sophisticated than a switchblade. Take away Jack's cautious forays into sexting, and this could be a story from the 1950s. There's certainly a timelessness both to the characters and the setting, a sense that these characters belong everywhere at once.