"Son of Rambow" shares a likeness to the recent Jack Black picture "Be Kind Rewind," most notably in the comic premise of amateur filmmakers remaking studio films and in an ending in which the finished product is bittersweetly unveiled. What came off as too stickily sentimental in "Be Kind Rewind" is more touching here because writer-director Garth Jennings (2005's "The Hitchhiker's Guide to the Galaxy") doesn't seem to be trying so hard. Instead, he keys in directly on the beauty and power that the art of cinema can hold, and backs it up with a complicated yet innocent onscreen friendship that rings true.

Preteen private school classmates Will Proudfoot (Bill Milner) and Lee Carter (Will Poulter) would at first appear to mix about as well as oil and water. Will dutifully follows the rules and is kin to a deeply religious family rooted in the Plymouth Brethren. Lee is a rebellious troublemaker whose wealthy parents are often out of town, leaving him saddled under the aloof care of older brother Lawrence (Ed Westwick). After getting into a scuffle, Will finds himself going home one day after school with Lee. It is here that Will first sets eyes on a movie—one suspects it's the first time, anyway—and he is so taken by what he sees of "First Blood" that he opts to go behind the back of his strict mother (Jessica Stevenson) and help Will in recreating a remake-cum-sequel to the original "Rambo." As filming gets underway, other kids, most notably androgynous French exchange student Didier Revol (Jules Sitruk), take the initiative to get involved in the film—something that Lee is none too pleased about.

A slight but infectious British comedy, "Son of Rambow" charms in spite of a slim plot and sketchy character development. With two lead characters who are roughly ten and twelve years old, it would have been easy for the movie to have felt too cute and adorable. Instead, writer-director Garth Jennings treats Will and Lee with an uncompromising toughness. Both boys hail from suffocating home lives—in Lee's case, his parents are neglectful, and for Will, his devout mother shelters him from television, music, and anything else she sees as potential corruptible. Though different in personality, Will and Lee find a common ground in their ambitions to make a short film on their own, based upon an unlikely inspiration. Jennings is careful not to demonize Will's mother's beliefs—above all, she is a caring person who means well—even as he portrays Will as a boy hungry to experience what the world has to offer even if it means going against the way he has been brought up. As "Son of Rambow" delves into darker territory near the end, the film earns a certain emotional potency, and a late scene set in a hospital reminds of 1986's underrated teen classic "Lucas."

Newcomers Bill Milner and Will Poulter are remarkable finds as the impressionable Will Proudfoot and scruffy, troubled Lee Carter. Both young actors are total naturals, able to bring a simultaneous sadness and joy to their roles that speaks loudly to their understanding of character motivation and nuance. Poulter is a particular standout as Lee, a boy whose tough-talking ways masks more insecurity than he'd like to admit. The rest of the ensemble are quite secondary in their treatment within the script, though Jessica Stevenson (2004's "Bridget Jones: The Edge of Reason") does make a sympathetic impression as Will's mother.

Set somewhere around 1982-1983, "Son of Rambow" intermittently used period pop-rock music (Siouxie and the Banshees, Depeche Mode, etc.) to unobtrusive effect. It makes for nice background shading to a film that is likable, amusing, but not always memorable. Outside of Will and Lee themselves, the rest of the picture doesn't have the same firmly thought-out clarity. Since one or both of them is in every scene, though, this is a relatively minor quibble. The last scene of "Son of Rambow" is gently handled, but hits an undeniable emotional chord for anyone who has ever gone to the movies and been whisked away by the immersive magic of it all. The first ninety minutes may not be, but the last five are just about perfect.