Don't mistake "The Mighty" for one of the "Home Alone" movies just because there's a Culkin in the cast. Nor for that matter, should you confuse it with "Simon Birch," even though the two films have a lot in common.

No, "The Mighty" is better, a whole lot better, than either of those movies. It lacks the syrupy sentiments and heavy-handedness of the latter, which made the mistake of trying to adapt a well-regarded novel.

And though it, too, is based on a beloved book, the young adults novel "Freak the Mighty," this drama/fantasy succeeds because it doesn't try so hard to please.

Not that it's completely perfect, mind you. "The Mighty" seriously stumbles in its final third, with some ludicrous plotting. But it also features two incredibly appealing performances from teen actors Kieran Culkin (one of Macaulay's younger brothers) and Elden Henson.

They star as Kevin Dillon and Maxwell Kane, two junior high school students thrown together by proximity (they're neighbors) and because they don't fit in with their fellow students.

Kevin (Culkin) is intelligent and outgoing but is limited physically — he suffers from Morquio's Syndrome, a crippling, degenerative childhood disease. Max is huge for a seventh-grader, but his hulking size masks his shyness and lack of courage.

However, together the two form an almost unbeatable team — with Kevin providing the brains and Max the brawn. Once Kevin climbs Max's shoulders, they become Freak the Mighty, an imaginary knight who rights wrongs around town.

And though they do manage to do a few good deeds, there are a couple of things the two may not be able to overcome, namely the specter of Max's tragic past and Kevin's rapidly deteriorating health.

As mentioned, both young actors are terrific. Culkin is very convincing, and on top of his endearingly humble performance, Henson also provides some good voiceover work as the film's narrator.

Give director Peter Chelsom ("Hear My Song") some of the credit for not letting things get too maudlin and for letting the youngsters carry the show.

Of course, it helps that there are also some effective performances by the adult cast, which includes Sharon Stone as Kevin's loving mother, Gena Rowlands and Harry Dean Stanton as Max's grandparents and "The X-Files' " Gillian Anderson in an extremely deglamorized role.

"The Mighty" is rated PG-13 for violent slapping and jostling, vulgar references and use of vulgar slang and scattered profanities (mostly mild).