It’s trickier than you might think to translate a Saturday morning cartoon program into a live-action movie. The first challenge is figuring out who your audience is going to be. Is it the little kids who watch the cartoon now and want to see every detail replicated on the big screen (like the live-action “101 Dalmatians”)? Or is it the former little kids who want to see their memories of the show through a filter that is part retro, part camp, part irony (like the Brady bunch movies) and be able to recognize Scrappy-Doo, Pamela Anderson, and Sugar Ray’s Mark McGrath on sight? There is not a lot of overlap, and yet this movie tries to reach both. It ends up somewhere between a live action cartoon that is much too scary for most children and Saturday Night Live sketch that goes on too long for most teens.

The Mystery Machine crew has just discovered the secret of the ghost who captured Daphne (it’s a man in a mask!), when their egos collide and they decide to go their separate ways. Two years later, they find out that each of them has been hired by Mr. Mondavarious (Rowan Atkinson), whose Spooky Island theme park is a little spookier than he had in mind. Fred, Velma, and Daphne try to solve the mystery on their own, but find that they have to work together to find…well, this time it’s not a man in a mask, exactly.

The young stars have the voices down perfectly and do the best they can to bring the characters to life, but that only emphasizes how sketchy and shallow the cartoon characterization really is. Like the Smurfs, the Scooby-Doo characters each have only one basic attribute: Fred (Freddie Prinze, Jr.) is self-centered, Daphne (Sarah Michelle Gellar) wants to be more than the girl who has to be rescued all the time, Velma (Linda Cardellini) is the brainy girl, and Shaggy (Matthew Lillard) is the always-hungry slacker. Prinze, who will someday find a movie that will show off his considerable talent, has his best moments when Fred becomes something like a hip-hop zombie. Lillard has his best moments anytime he is not challenging Scooby to a flatulence and burping contest.

Parents should know that the movie has a lot of intense and scary special effects. The characters are in frequent peril, though no one gets hurt. There are a couple of mild swear words and some mild drug humor (as “Pass the Dutchie” plays on the soundtrack, what appears to be marijuana smoke turns out to be something else) and some vulgar jokes and graphic bathroom humor. The girls wear very skimpy clothes.

Families who see this movie should talk about why the friends broke up and why they got back together. They might also want to talk about what has made Scooby and his pals so enduringly popular over the years.

Families who enjoy this movie will enjoy the original Scooby cartoons like Scooby Classics (including the very first episode) and Scooby-Doo’s Spookiest Tales. If they want something a little spookier, they should try The Nightmare Before Christmas.