Grade: F

The success of the “Spy Kids” franchise, as well as of the “X-Men” movies (whose copyright holders actually demanded changes in the script) doubtlessly explains a movie like this, in which Tim Allen plays an erstwhile super-hero called out of retirement to train a group of youngsters with special powers to confront a threat to the world. But Robert Rodriguez’s follow-up to his boffo trilogy, “The Adventures of Shark Boy and Lava Girl,” showed how difficult is it to pull off this sort of thing (so did “Thunderbirds”), and “Zoom” lacks any of the wit or charm of “Sky High,” the only picture to handle a similar premise at all engagingly. Certainly this example is a particularly awful one.

In the screenplay, based on the comic mini-series by Jason Lethcoe, Tim Allen plays Jack Shepard, who was once superhero Captain Zoom until, in a victorious but costly battle against the villainous Concussion–who, we will eventually learn, is actually his brother (Kevin Zegers) turned to the Dark Side by governmental experimentation–he lost not only his powers but all the other members of his Team Zenith. Now the guys behind the old Zenith program–spit-and-polish General Larraby (Rip Torn) and goofy scientist Dr. Grant (Chevy Chase)–are trying to restart the team in response to another threat to humanity, which turns out to be (to Jack’s astonishment) the return of his brother from another dimension. They intend to enlist four youngsters with super powers found by Dr. Holloway (Courteney Cox)–Tucker (Spencer Breslin), a chubby kid who’s like the old Colossal Boy; Dylan (Michael Cassidy), who can turn invisible; Summer (Kate Mara), who’s capable of telekinesis; and Cindy (Ryan Newman), who has super strength–as the new team members. But they need to be trained. And so they call in the reluctant, abrasive Shepard to play mentor to them.

It goes without saying that Jack eventually warm up to the kids and they hone their powers and learn to work as a team. It’s also easy to predict a romance between Shepard and the accident-prone Holloway, who idolizes Zoom, and a conclusion in which Concussion will be brought back to the side of Right. What isn’t is say that one can foresee just how bad the movie is. The humor is lame, with the obligatory quota of flatulence jokes and goopy gags, and the script gets even worse when it goes sappy and saccharine. Peter Hewitt’s direction is slapdash, and the effects would barely pass muster on Saturday-morning television. (In fact, all the technical aspects of the picture–from Barry Chusid’s chintzy production design to David Tattersall’s glaring cinematography, are sub-par.) And Christophe Beck’s insanely upbeat score drives you crazy, although he might not have been responsible for the dreadful array of pop tunes chosen to accompany the endless montages Hewitt has inserted to bloat up the running-time.

But it’s the cast that takes things to the nadir. You can’t blame the kids overmuch, though Mara and Cassidy are bland, Newman gratingly cute, and Breslin annoying (it’s amazing that with an epidemic of childhood obesity in America, his character’s excessive weight–a fat-suit is employed–would be made a joking matter). But Allen’s stentorian approach is terribly misjudged, and the requirement that Cox slip and fall every ten minutes gets old fast. But they nonetheless come out unscathed compared to Chase and Torn. The former, looking puffy and glazed, tries to revive his old doofus shtick with deadly result; a scene in which he’s trapped in an “outdoor test machine” by the kids is so terrible it must be seen to be disbelieved. And Torn, looking wrinkled and worn, bellows to absolutely no humorous effect. And one grieves to see Zegers, fresh from his fine turn in “Transamerica,” forced to pose and shout so tinnily in the big final confrontation. I suppose young actors need to takes some parts just for the paycheck, too.

Back in 1999 Allen had one of his happier cinematic moments in the cheesy but nimble “Galaxy Quest,” which riffed jovially on “Star Trek.” But this juvenile take on “X-Men” or “Fantastic Four” is an even worse genre spoof than the gender-bending “My Super Ex-Girlfriend” was earlier this summer. In terms of age level, “Zoom” stands somewhere between “Baby Geniuses” and “The Adventures of Pluto Nash,” but it’s just as bad as both of them.