I dreaded "Scooby-Doo" like a caramel addict dreads a trip to the dentist. The succession of bad cartoons turned into worse movies was already long, and "Scooby-Doo" promised to be the worst yet.

Do you have any idea how bad a movie must be to be worse than "Josie and the Pussycats" and "The Flintstones in Viva Rock Vegas"?

It was the three-strike rule. First, "Scooby-Doo" had a suspect director, Raja Gosnell, whose credits include "Big Momma's House" and "Home Alone 3." Second, it had an untested screenwriter, James Gunn. And third, it starred Freddie Prinze Jr., who may be the source of all evil in the universe.

But as the theater lights dimmed and "Scooby-Doo" unspooled, a strange thing happened: The movie didn't stink. In fact, it was moderately amusing.

I say this as someone who is not a fan of the cartoon series, which became tiresome even before hated sidekicks Scooby-Dum and Scrappy-Doo showed up, to say nothing of Flim Flam.

Yet the movie works because it remains faithful to its source material. Rather than simply parodying "Scooby-Doo," the movie takes the cartoon to its logical conclusion.

This is one time when we can thank the studio for meddling in the creative process.

"Scooby-Doo" fans have speculated for years about whether Shaggy is a pothead and whether Velma is a lesbian. And what, exactly, are Fred and Daphne really up to when they're supposed to be searching for clues?

Reportedly, an earlier cut of the movie did more than drop hints, which upset Warner Bros. executives, who didn't want a PG-13 rating and angry soccer moms on their hands.

So, most of the suggestive material stayed in the editing room, and the movie is probably better for it. In this case, the humor comes from the ambiguity.

As "Scooby-Doo" opens, Mystery Inc. is falling apart.

Fred (Prinze) is letting his ego run wild. Velma (Linda Cardellini) is tired of Fred taking credit for her plans. And Daphne (Sarah Michelle Gellar) hates always being the damsel in distress.

They go their separate ways, leaving best buddies Shaggy (Matthew Lillard) and Scooby (voiced by Scott Innes) to fend for themselves.

The action jumps ahead two years, when an island amusement park's owner (Rowan "Mr. Bean" Atkinson), recruits the reluctantly reunited Mystery Inc. gang to discover who is turning his guests into zombies.

From there, the movie unfolds like an elaborate version of the cartoon.

Although Prinze and Gellar get top billing, it's Lillard and Cardellini who carry the movie. Their impersonations of their cartoon alter egos are uncanny. They nail the voices, the movements and the personalities.

Cardellini is a breakout star, helped by the fact that even though she plays a geeky character, she is only "Hollywood ugly." By that, I mean she is really a babe, given a bad hairdo and nerdy wardrobe to try to hide that fact.

As a result, smart girl Velma has 10 times the sex appeal of anorexic cover girl Daphne. In fact, a couple of the movie's better jokes are at the expense of Daphne's (and, by extension, Gellar's) near-terminal thinness.

Gellar, meanwhile, plays Daphne as a lightweight version of Buffy the Vampire Slayer. The script takes advantage of Gellar's presence by having Daphne learn karate, which is a good idea for someone who is always getting captured by old men who wear funny costumes.

Prinze's Fred, however, is left with little to do except be the butt of most of the jokes, which is just as well. Based on past performances, that may be the limit of Prinze's talent.

That leaves Scooby.

As far as computer-animated characters go, Scooby-Doo isn't as lifelike as Jar Jar Binks, but he isn't as annoying as Jar Jar, either. And the filmmakers wisely don't let Scooby overshadow his human costars.

"Scooby-Doo" won't disappoint fans of the cartoon. And even casual viewers may find it worth the matinee price.