Grade: C

The Harry Potter template hangs heavy over Chris Columbus’ adaptation of Rick Riordan’s first book in his series about the titular teen, who’s actually a demigod—the son of the Greek god Poseidon and a mortal woman, Sally Jackson—who learns his Olympian paternity when he’s wrongly accused of stealing Zeus’ thunderbolt and must find, and return, it in order to save the world. He’s also quickly enrolled in an outdoors demigod school that’s actually called Camp Half-Blood, but might as well be named Hogwoods. (Or is that Hogwash?)

At first glance Percy (Logan Lerman, most recently seen in the dreadful “Gamer”) seems a normal kid, albeit one suffering from dyslexia, living with Sally (Catherine Keener) and his smelly, abusive stepfather (Joe Pantoliano)—who’s actually named Ugliano. But when he’s attacked by a CGI fury, he’s saved by his supposedly crippled teacher (Pierce Brosnan) and best pal (Brandon T. Jackson), who turn out to be hiding their legs because they’re actually a half-horse centaur called Chiron and a half-goat satyr named Grover. They spirit Percy off to the camp, where after a battle with a nasty CGI minotaur, he starts his training along with a raft of other demigods and quickly bonds with Annabeth (Alexandra Daddario), a daughter of Athena, and handsome Luke (Jake Abel), a son of Hermes.

This is one strange camp. These youngsters—who supposedly have special powers as a result of their status (Percy, for example, thrives in water and proves to have control over it)—aren’t trained in the development of those abilities. Rather they’re dressed up in ancient battle garb and encouraged to thwack away at one another with swords and maces and learn to use bows and arrows. Why is unclear.

But it doesn’t really matter, because Percy doesn’t stay long. Learning that Sally has been carried off to the underworld by Hades (Steve Coogan), who wants that stolen thunderbolt in order to seize power from Zeus (Sean Bean), he escapes to free her, accompanied by Annabeth and Grover and armed with some winged slippers and a special shield supplied by Luke. The quest requires them to collect three pearls that will allow them to leave the underworld safely after completing their mission—a job that takes them to a dangerous meeting with the villainous Medusa (Uma Thurman, doing a Cruella De Vil impression), to a mock-up of the Parthenon in Nashville, and to a casino in Vegas that’s a modern equivalent of Odysseus’ Land of the Lotus Eaters, the place of forgetfulness. Eventually they overcome all obstacles to save Sally, confront and defeat the real thief—though even ten-year olds will probably have guessed his identity long before—and have a peace-making meeting on Olympus with Zeus and Percy’s long-absent dad, Poseidon (Kevin McKidd).

There’s nothing wrong with this jumble of classical mythology—which the characters obligingly explain as the particulars come up, assuming (quite rightly, one suspects) that today’s kids won’t get the references. It all has the feel of a juvenile retooling of the sort of stuff Ray Harryhausen used to do with his stop-motion efforts (“Jason and the Argonauts” and especially “Clash of the Titans,” which the last scene here especially recalls—naturally it’s being remade, too)—which for some of us gives it a nostalgic glow. Of course, the effects technology is slicker here, though hardly eye-popping—the CGI work isn’t appreciably better than that one will see on television nowadays on “Smallville” or even live-action movies on the Disney or Cartoon networks. But it’s certainly okay.

There isn’t a great deal of charisma among the young cast, either. Lerman seems a pleasant kid, but rather bland and anonymous, and the same could be said of Daddario and Abel. Jackson’s a different case—he’s supposed to be the with-it comic sparkplug, and exudes entirely too much energy, constantly saying stuff like “That’s what I’m talking about!” to connect with the target audience. It’s more irritating than charming to an adult viewer, but younger boys may feel more charitably disposed toward him. Among the adults, Brosnan seems to be having fun doing the centaur bit, and Keener shows some intensity, but the rest generally just go through the motions and try not to look embarrassed wearing togas. Columbus’ direction mirrors his work on the first two “Potter” movies—the weakest of the lot—and Stephen Goldblatt’s cinematography is adequate but no more. Christophe Beck’s score has nothing like the memorable quality Bernard Herrmann brought to Harryhausen’s pictures (among them “Jason”).

Studios keep falling over themselves trying to find the next kid franchise, the next Harry Potter. But whether it be the Lemony Snicket picture, the “Spiderwick” one-shot, or the recent “Cirque Du Freak” movie, nothing has clicked. And while “Percy Jackson” certainly isn’t terrible, it plays like a low-rent variation of the Harry Potter formula—innocuous but instantly forgettable. Boys under ten or so may enjoy it, however—though probably on DVD or Blue-Ray.