I have to admit being a complete sucker for mysterious island/lost continent/hidden valley/ forgotten world yarns — they remind us that, even on a planet that has been Google-mapped and subdivided, there is still a bit of mystery and adventure out there. A great adventure film can make you feel like you’re a 10-year-old kid all over again.

Alas, "Journey 2: The Mysterious Island" is aimed right at kids, and kids only. Adults are invited along simply as grumpy chaperones. The movie aims low and hits its preadolescent demographic target squarely, so it succeeds on its own terms, but only on its own terms. So I guess it’s a success.

This is a sequel to "Journey to the Center of the Earth," made half a decade ago. It starred Brendan Fraser and helped kick off the current 3-D movie-marketing insanity. This sequel is made by a crew of dedicated Hollywood sequelists — it must be a particularly nasty ghetto — and the only thing remotely clever about it is the Twitter-like pun of the title.

The sole returnee is young Josh Hutcherson, now teetering on teenager-dom, stewing about his lost grandfather, played by Michael Caine. Hutcherson’s newly acquired stepdad, played by Hawaii’s Dwayne Johnson, is a concerned lout with some sort of Navy intelligence training. Between them, they piece together a map out of arcane literary references and hele on to Palau, in the equatorial Pacific.

They hire a cowardly helicopter pilot and his snooty, beautiful daughter to get them to the coordinates. There, they tackle one 3-D theme-park ride after another until the movie is over. We’re talking giant bees and tiny elephants and monster lizards and Johnson’s pectoral muscles, which seem to be a special effect all their own.

Hey, it moves right along. It rockets on a certain goofy bliss. Never mind that the filmmakers clearly never have read the original Jules Verne/Robert Louis Stevenson/Jonathan Swift books beyond their cover blurbs, or that their notion of geology is hilariously imprecise. Volcanos that spew molten gold? Not to mention a stupendous misdiagnosis of the geologic process of soil liquefaction.

And, why are lost worlds in Hollywood movies always doomed to be destroyed by the last reel? Kind of screws up the sequel to the sequel.

PARTS OF the film were shot in Hawaii and look great, and others in North Carolina and look terrible. Just kidding — there’s so much accreted CGI slathered onto the images it’s hard to figure out what’s where, and where’s what. It adds, however, to the artificial theme-ride groove.

Although the film is built upon the marketing bonanza of a 3-D experience, that experience is still like watching a movie through smudgy sunglasses. See it in 2-D.

Caine, looking exhausted but chipper, must have had a mortgage payment due. Hutcherson is distinctly unmemorable. Luis Guzman, as the helicopter pilot, is vaguely ethnic and makes infantile "jokes" throughout. Which means most of the film’s weight falls squarely on Johnson’s impressively broad shoulders. Luckily, he has gallons of charisma. Hugely aware of the camera, he does everything but wink at the audience in every scene.

And Vanessa Hudgens, spending the entire film in high-riding short-shorts and a damp, clingy tank top, serves as a glowing beacon to preadolescent boys of yet-greater mysteries ahead in life. But that’s a different movie.