In voice-over, Will claims that his life is full and fun, but to owe one’s well-being to something called “Santa’s Super Sleigh” causes some moments of excruciating embarrassment. Of course, there are more embarrassing things to suffer in life. Hugh Grant has lived through a profoundly embarrassing incident, and he seems to channel this emotional memory to bring Will’s humiliation to life. As Will wanders in the grocery store, in early November, and the dreaded song signaling the beginning of the Christmas season booms over the sound system, Will’s cringe takes in body and soul. This is a wonderful role for Grant, and he gives the role of the immature Will the most mature performance of his career.

Will, not the boy of the title, but still very much an adolescent inside his adult form and designer clothes, is grotesquely charming and almost sympathetic but truly a louse when the picture begins. He has carefully crafted habits to support his contention that, contrary to the conventional wisdom that “No man is an island,” he is in fact an island. To maintain this notion all relationships are disposable. He wants and needs female companionship, and to keep a steady supply of women available he begins attending meetings of SPAT, Single Parents Alone Together, and invents an imaginary son, Ned, to help him lure ladies into his life.

At a SPAT picnic, he meets Marcus, the son of a friend of the woman he’s trying to fool. Marcus, played with a very likeable naturalness by Nicholas Hoult, is 12 and he has problems. His parents are divorced. He’s in a new school. His mom, Fiona (Toni Collette) is a depressed and extreme freakish hippie who imposes her habits, beliefs and third-world fashion sense on her very sweet, very unwitting son. In the schoolyard, while his schoolmates wear hip dark urban outfits, Marcus stands out in colorful horribly unhip contrast.

Marcus is such a hopeless case that even the other geeks at school tell him they have to stop hanging out with him because suddenly, because of him, they are attracting daily harassment from bullies who formerly left them alone.

Marcus’ life goes from bad to worse when his mother attempts suicide. Will, who happens to be present when she is discovered unconscious, is forced into service helping this unhappy pair. Will’s main impression of this event is how cool it is to speed to the hospital behind the ambulance.

Marcus starts following Will and discovers that son Ned is surely a fiction. He uses this information to blackmail Will into letting him come by after school and watch television and hang out. Marcus needs a refuge from the sadness at home. Will needs just the kind of undemanding human contact Marcus provides.

Will, despite himself, can’t help getting involved with Marcus. All of the mostly useless lifestyle information that dominates Will’s life can actually be put to use helping Marcus suffer less. A pair of hip training sneakers has never figured in a story quite so endearingly. The two are frighteningly about par when it comes to emotional maturity. In fact, Marcus is probably slightly ahead of Will.

As Fiona’s depression starts creeping back, Marcus hatches a plan to get Will and Fiona together. That way Marcus will have “back up.” By his reasoning two people aren’t enough. You need three people, so if something happens to one, there are still two people to take care of each other.

The fixing up doesn’t take, and soon both Will and Marcus have crushes on girls. Rachel Weisz plays Rachel, Will’s crush. She has a 12-year-old son, and Will uses Marcus as a stand in son to buy himself a little time and credibility with the lovely Rachel. Will gets burned by Rachel and retreats to his island, but he can’t stay there because Marcus needs him. Will is forced to acknowledge that he cares about Marcus and has to try to protect him.

About a Boy has been adapted from Nick Hornby’s novel by Chris and Paul Weitz, the brothers behind the American Pie franchise. Hornby’s novels are gems of pop culture details and the kind of struggles that may not amount to a hill of beans in this crazy world but are the common plagues of modern life and love. High Fidelity moved pretty easily from London to Chicago.

About a Boy stays in London, but the Weitz brothers have made changes to the novel’s ending. They’ve only made the story better suited for the screen without tampering with the delicate and touching relationships at the

center. About a Boy is a very welcome departure from the American Pie sensibility. There is not a gross-out gag in sight. As directors, they manage this slight story well, pulling humor out of subtle and gentle performances.

About a Boy does culminate in a sight gag scene. Hornby, as his fans know, is obsessed with pop songs. About a Boy involves Marcus and Will in a performance of “Killing Me Softly” that is nearly as cringe-inducing as owing your livelihood to a pop song named “Santa’s Super Sleigh.”

But through great embarrassment comes growth. This torturous performance helps win Will a girlfriend and Marcus the chance to go to McDonalds. The man learns to be a man, and the boy gets to be a boy.