Nick Hornby

When you have to describe the plot of “About a Boy” in 25 words or less, you say it’s about an immature lout who learns how to be a grown-up by befriending an odd little boy — which is essentially true, although it makes the story (as told in both the movie and the Nick Hornby novel it’s based on) sound much gloppier than it is, like “A Christmas Carol” crossed with “Peter Pan.”

More specifically, “About a Boy” is about the way human beings trade information and observations and feelings with one another, and about how others can sometimes make you see your way toward being the person you didn’t even know you wanted to be. It’s also about the ways parents unwittingly cripple their own children with their love, even by doing something as seemingly small as making them wear a goofy sweater to school.

When parents tell their children (as they rightly should), “Individuality is wonderful! Embrace it!” it’s sometimes their own individuality they’re championing, after having firmly imprinted it on their kids. Without being churlish or mean, “About a Boy” shows us how hard it is for parents to grow up, too, suggesting that letting your child become his or her own person might be the final and most important (not to mention the most difficult) act of shedding your own childhood.

Hornby’s novel is sweet, if slight, and eminently enjoyable as a pop-culture snapshot. It’s also an honest rumination on the way material goods, as expressions of our own personal style, sometimes have a value far beyond their actual cost. But while Hornby’s characters were sharply drawn, his story was diffuse and meandering. The movie, directed by the team that gave us “American Pie,” Paul and Chris Weitz, captures the essence of Hornby’s story and sharpens the edges: It’s faster and funnier and sleeker than the book, and its distinctive stylization really makes Hornby’s ideas gel.

The Weitzes’ “About a Boy” moves along swiftly, swerving and curving around every obvious pothole; the directors take care of every detail without spelling out the obvious for us. For once, we’re simply left to use our intelligence and wits as the story unfolds before us. That should be the rule, and not the exception, in mainstream movies, yet it has become increasingly rare. “About a Boy” is as close to mainstream perfection as I’ve seen all year. It gives us everything we want, need and deserve without batting an eye.

Hugh Grant plays Will, a spoiled arrested adolescent who doesn’t have to work because his dad wrote a hit Christmas song years ago; the royalties keep rolling in as sure as December keeps rolling around. (When a prospective girlfriend asks him, with wide-eyed curiosity, if even door-to-door carolers need to pay for the privilege of singing “Santa’s Super Sleigh,” Will responds tartly, and at least half-seriously, “They should, actually, but you can’t always catch up with the bastards.”)

Will has a slick London apartment loaded with lots of cool toys, and nothing to do but fill his days with TV watching, pool playing and hunting around for women whom he’ll date for a while and then unceremoniously dump. After a friend hooks him up with a recently divorced single mom, he realizes he’s hit the jackpot: Single mothers are exceedingly grateful for every bit of attention shown them, which makes them much less demanding than your ordinary, garden-variety girlfriend.

To meet more of these spectacular creatures, Will invents a child for himself and attends a meeting of a local single-parents group called SPAT, for Single Parents Alone Together. That’s how he eventually comes to meet 11-year-old Marcus (Nicholas Hoult), the shuffling, Peruvian-knit-sweater-wearing child of a perennially depressed arrested hippie and music therapist, Fiona (Toni Collette).

To call Marcus an awkward kid is an understatement: At school, even the little Pakistani computer nerds, the lowest fishies in the schoolyard pond, inform him solemnly that he can’t hang out with them anymore. We know the kid’s really in trouble when we see his mother, her ethnic earrings dangling cheerfully in cruel contrast with her dour, tear-stained face, sprinkling the morning breakfast cereal into bowls: It’s called Ancient Grains.

It takes forever for Will to warm up to Marcus, which is one of the great joys of “About a Boy”: Any transformation that’s going to stick can’t be easy, so we relish the long, stretched-out moments in which Will finds dozens of ways to tell Marcus to buzz off. Their friendship isn’t a sudden click; it’s more of a gradual erosion, the sort of thing that eventually turns beach glass back into sand, with Marcus doing the grinding. The evolution of their friendship is charted cleverly in a montage that shows Marcus, day after day after day, ringing Will’s doorbell after school and plopping himself down on the couch, despite Will’s obvious protestations, as if it were the world’s most eminently reasonable act.

Marcus isn’t immediately lovable: He’s as weird and annoying to us as he is to Will, with his assertively all-wrong clothes and his tendency to blurt out the lyrics of soppy ’70s songs at inappropriate times. But as Marcus is written (the screen adaptation of Hornby’s book is by Peter Hedges) and, even more important, as Hoult plays him, you can’t help warming to him.

Marcus’ walk, a kind of flat-footed shuffle in which his legs move independently from his rigid torso, at first represents everything about him that’s closed off and fearful: By the movie’s end, you see it as something different, a natural trait that somehow matches how open and funny and free this kid is. Hoult, with his devilishly unkempt eyebrows and cherubically too-red lips, plays one of those pre-teens who still looks too much like his mother’s little boy, and your heart goes out to him — Hoult doesn’t try to grab it from you, as so many child actors do.

Collette, as Fiona, has an even tougher job: Here in the early 2000s, we all recognize that it’s perfectly acceptable to laugh at hippies who just can’t let go of their security ponchos. Collette actually invites us to; indeed, how can we avoid it, when Fiona shows up for a lunch date with Will in a hairy monstrosity of a sweater that Will later characterizes as a “Yeti costume”?

But Collette also pulls off the more difficult feat of making us feel something for her every step of the way. Fiona is suicidal, but even though we’re aware of her pain, we also see how much it hurts Marcus. (“I feel better now,” she says simply, beaming calmly at him after she returns from a stay at a mental hospital, as if his loneliness and confusion were mere accessories to her own smoothed-over feelings.) Collette forces us to acknowledge both Fiona’s suffering and her selfishness, a tricky line to walk.

She bounces brilliantly off Grant’s Will, whose annoyance with her boils into frustration and then full-blown rage, when he confronts her with the ways in which she’s “made” Marcus so weird. “You daft fucking hippie!” he hurls at her, and the line is as funny as it is cruel and weirdly poignant. Grant, who used to hide far too coyly behind his public-schoolboy stammer and floppy forelock, has turned into a marvelously unself-conscious actor. He’s best when he’s playing a bit of a bastard: The evil glimmer in his eyes when he spied Renée Zellweger’s giant granny underpants in “Bridget Jones’s Diary” was one of the sexiest things I’ve seen at the movies in years.

Grant’s also an incredibly game actor: He gives it the full throttle, in his inimitably understated way, when he explains to two of his sunshiney, new-parent friends that he can’t possibly be their infant’s godfather because he’ll only be trying to put the make on her when she turns 18. It’s a hilarious moment, but even more remarkable is the way Grant’s resolute orneriness meshes with the person he becomes later in the movie.

When Will notices that Marcus is wearing the dorkiest shoes on planet Earth, he buys him cool new trainers — Will is grimly determined that the shoes will be what helps this kid through the roughest years of his life, and in a roundabout way, he’s right. Grant is wonderful here because he recognizes that a character can soften without turning into a marshmallow. He’s also, I have to note, aging beautifully: He has never looked as handsome as he does here. Those few inklings of crow’s feet are the best thing that could have happened to his impishly good-looking face.

Every performance in “About a Boy” moves naturally and beautifully in concert with the others. It’s a movie that works on every level, starting at its very core. It’s the movie the Weitzes were destined to make. They aren’t known as subtle directors, although they should be: “American Pie,” at first written off as a shallow teen gross-out comedy, has actually found an audience that sees its larger value; for one thing, no teen movie since “Fast Times at Ridgemont High” has shown so much sensitivity toward teenage girls in the face of boys’ sexual cloddishness. The Weitzes’ second feature, “Down to Earth,” didn’t resonate as clearly but was nonetheless wrongly overlooked: It’s a sweet-natured and well-made entertainment.

But neither picture comes together as wholly as “About a Boy.” Its apparent lightness is actually many-layered: The Weitzes are masters at playing two (or, more often, many) emotions off one another at once. When we see Fiona and Marcus gathered round their tinkly home piano, belting out a rousing and stupendously earnest rendition of “Killing Me Softly,” we wince, just as Will does. Then, just as it does with Will, our vague amusement at the ridiculousness of it all transmutes into something like horror. And yet, even as we’re howling with laughter at them, it’s impossible to feel derision — their belief in the power of this lousy song transcends its innate crappiness, and we see them, and the bond between them, as something inherently wonderful despite its corny trappings.

That’s a pretty subtle thing for two directors, best known for a movie in which a teenager humps a piece of pastry, to pull off. But then, “About a Boy” is all about the process of becoming something that no one, least of all yourself, ever thought you could be. The Weitzes have topped themselves, and their movie is an invitation to us to tap the better parts of our nature, without resorting to cheap self-congratulation. The not-so-secret message of “About a Boy” is that people are bastards. And bastards are so much easier to love than saints.

Mulligan plays 16-year-old Jenny, a bright student who lives with her mother and father (played by Cara Seymour and Alfred Molina) in the suburbs of London. Her parents, as well as one of her teachers, Miss Stubbs (Olivia Williams, of “Dollhouse”), have high hopes for her: The plan is that she’ll go to Oxford, and her father, in particular, orchestrates her life with that goal in mind. He doesn’t even want her to practice the cello too much, seeing it as a diversion that isn’t wholly necessary for academic success. Jenny finds solace lounging alone in her room, listening to French pop music — the enormous, romantically sooty eyes of Juliette Greco stare out from one of the album covers scattered about her room — and dreaming of a sophisticated, cultured life that’s far beyond her reach.

And then she meets David (Sarsgaard), a fellow music lover who takes what is at first a rather harmless interest in her, even though it’s clear he’s approximately twice her age. He charms her parents into letting him take her to a concert. Before long, he’s also taking her out to nightclubs with his upscale friends, Helen and Danny (Rosamund Pike and Dominic Cooper). David has money (although, it turns out, his line of work isn’t particularly savory), and he knows how to enjoy it. Jenny thrives under his tutelage and in the glow of his attention. And to Jenny’s delight, Helen, a cool blonde with a taste for fitted brocade and snowy furs, remakes her into a sophisticated gamine: Jenny loves flitting about London — and, at one point, Paris — in trim sheath dresses and Audrey Hepburn updos, a far cry from her usual schoolgirl gear.

Eventually, of course, there will be a crisis, and we’ll learn that David isn’t exactly what he seems — or maybe the point is that he is exactly what he seems, and Jenny just can’t see it. Either way, Scherfig treats the affair as a real relationship, not as a schoolgirl fantasy; she doesn’t patronize her lead character by making her seem foolish or flighty. The point is that Jenny’s desires are real — they may be shallow or misguided, but that doesn’t diminish their hold on her, and she’s the one who has to work them out of her system.

Scherfig and Hornby understand that, which also frees the actors. Sarsgaard, in particular, has a challenging role. He’s a handsome question mark; we know he’s too good to be true, and deep down, Jenny probably does, too. The movie doesn’t quite know what to do with him, and in the end, it makes him into the worst kind of coward — when, really, he needs to be only a minor coward to make the story believable. Even so, he isn’t an easy figure to pin down. David is Jewish, and he knows how to make money: The movie is clear about that fact. But that may not be so much a mark of anti-Semitism as it is of plainspoken emotional logic. The idea, I think, is that being Jewish in 1961 Britain is enough to put a chip on your shoulder. No wonder David is a social climber, aspiring to prove himself worthy of a certain class of people, or of a certain kind of girl who has more innate class than he does.

The love scenes between David and Jenny are sweet: David doesn’t seem predatory so much as perpetually confused, and Jenny, despite her romantic expectations, is in many ways more realistically grounded than he is. The two do sleep together, and the sequence is handled delicately and intelligently — Jenny may be inexperienced, but she’s not a pushover. Scherfig takes care to make it clear that Jenny’s choices are risky for the time in which she’s living — she doesn’t frame Jenny as an anachronistic, pre-sexual-revolution heroine. At the same time, she doesn’t pretend shock and dismay that young people actually had sex in the days before sexual liberation. Her approach doesn’t treat sex as a novelty, but as a fact of life. And the movie is compassionate toward nearly all its characters: Helen, as the crisp and wonderful Pike plays her, looks like a class act, but she’s dismayed by Jenny’s attempts, awkward as they are, to speak French — it’s clear she doesn’t have anything close to Jenny’s smarts, and she hides her insecurity with a veneer of coolness.

Scherfig makes it easy to see why Jenny would be seduced by the life of culture and glamor that David offers. The movie, shot by John de Borman, shows London and Paris as beautiful, lavish playlands. It’s pleasurable to watch Jenny enjoy herself in this newfound paradise: Mulligan has just the right blend of coltish awkwardness and ageless common sense. And although Jenny is clearly enjoying David’s attentions, Mulligan makes us see that the character is always working hard to read the people around her. She wants to be in love, and she wants it to be easy; but there’s always a shadow of uncertainty in Mulligan’s eyes — as inexperienced as Jenny is, she knows deep down that love can never be easy. And while the movie’s conclusion may be a little too facile, it doesn’t hold even a whiff of “I told you so” lecturing. Scherfig allows Jenny both her youthful joy and her dignity. And it allows that one of the bittersweet gifts of sexual adulthood is the freedom to make your own mistakes.