Odds are it’s not easy to find tons of college-aged fans ­— or fans over five years old — of 2008’s “Journey to the Center of the Earth.” Even so, producers have risen to the non-existent demand for a sequel and made “Journey 2: The Mysterious Island,” a film with an almost identical plot, with Dwayne “The Rock” Johnson taking the action hero reins from original star, Brendan Fraser.

Much like the first film, “Journey 2” finds Sean (Josh Hutcherson) dragging an unwitting father figure (Johnson, his mother’s boyfriend, Hank) into an adventure to find his grandfather (Michael Caine). Their journey leads them to a titular mysterious island, where Sean and Hank quickly find themselves trapped, along with tour guide Gabato (Luis Guzman) and his daughter Kailani (Vanessa Hudgens).

On the surface, “Journey 2” is a forgettable, lazy follow-up to a film that no one liked much in the first place, and it’s easy to label it as such. After all, its teenaged hero is a stock rebel without a cause (with boatloads of daddy issues to boot), and his only character trait is an encyclopedic knowledge of Jules Verne novels. Even worse is Guzman’s role as a woefully misguided tour guide who exists solely to provide bizarre, markedly unfunny comic relief. It’s too bad “Journey 2” isn’t just lazy; it’s aggressively stupid.

If there’s one thing a movie needs, it’s a sense of internal logic. A film needs to be able to build a world that viewers can invest in. Otherwise, it fails on a basic level and makes it incredibly easy to recognize all the flaws and inconsistencies, of which “Journey 2” has many. While miniature elephants and giant lizards add to the undeniably impressive spectacle of the film, the size of the characters in relation to the world around them is in constant flux. Characters can go from walking through a normal-sized jungle to evading gargantuan birds through trees hundreds of times their height in the blink of an eye, and that’s just one of many nonsensical elements the film tries to explain away with shoddily written pseudo-science.

As a pure, goofy spectacle, “Journey 2” almost works. The stupidity of its script keeps it watchable, if only to see where it’s going to go next, and the film’s special effects are undeniably strong. Caine looks like he’s laughing all the way to the bank in this film. He earns every dollar of his check with a big, silly performance. Meanwhile, Dwayne Johnson continues to impress as an action hero. Johnson was the best part of last year’s “Fast Five” and he’s game for whatever the script throws at him here. Even if he never quite creates a character, Johnson makes the audience believe he’s certainly having a good time traipsing around this island, and in a better movie, his enthusiasm might be infectious.

“Journey 2” won’t win any fans over to the “Journey” franchise, and as a narrative, it’s a poorly constructed, laughably terrible failure. As a silly, 90-minute diversion, there are certainly better films out right now (“Haywire,” for example), but adolescents who haven’t graduated past the PG rating yet should enjoy “Journey 2” enough for all of us.

Printed on Friday, February 10, 2012 as: Redundant sequel lacks logic, should be left to feeble minded