There's a distinct difference between eccentricity and everyday normality, yet somehow "Lawn Dogs" manages to blur the line separating the two.

This low-key comedy-drama, about the unusual but innocent friendship between a lonely 10-year girl and an ostracized groundskeeper holds up for most of an hour, thanks to charming performances by Sam Rockwell and talented young newcomer Mischa Barton.

But in the final third, the film finally gives in to its own innate weirdness, with a fantasy plot twist that robs the story of some of its power. Still, it is likable enough, and the offbeat sense of humor certainly doesn't hurt.

Barton stars as Devon Stockard, whose family has just moved to the affluent Camelot Gardens subdivision. Unlike her social climber parents (Christopher McDonald and Kathleen Quinlan), she has no desire to befriend the other residents.

Instead, the youngster has a "secret" friendship with Trent Burns (Rockwell), the twentysomething outcast who mows lawns for her father. She sneaks out every night to hang out with Trent, with whom she shares stories, both real and imagined.

However, their friendship has not gone unnoticed, which lands Trent in hot water with Nash (Bruce McGill), the Camelot Gardens security guard, and a pair of college boys (Eric Mabius and David Barry Gray) who don't like his smart-mouthed attitude.

Screenwriter Naomi Wallace's story takes some weird turns, but none as odd as the "twist" ending, which almost ruins the whole thing. And her efforts to make the other characters seem villainous is pretty dishonest — and doesn't make it easy for the actors playing them.

Fortunately, director John Duigan ("The Journey of August King") wisely concentrates on the interaction between the two lead characters, who are terrific. In fact, Barton and Rockwell are so likable that it's easy to overlook the movie's most glaring faults.

"Lawn Dogs" is rated R for violent gunplay and a vicious animal assault, profanity, vulgar jokes and use of vulgar slang, full male nudity, simulated sex and use of racial epithets.