“Monster Trucks”

*1/2

(PG, 1:44)

“Monster Trucks” starts out with a relatively adult, science fiction premise: that our current obsession with fracking could threaten underground, intelligent creatures unknown to us. Then the film overwhelms this idea with an utterly childish conceit: These same creatures, who each could fill a living room, guzzle gas, hang out with humans, and love — just love — to inhabit big trucks.

Huh? It sounds like a cartoon, which this movie should have been. But this is a live action feature, and “Monster Trucks” unwittingly makes yet another compelling case that laborious special effects offer no substitute for the emotional heft that a project like this needs.

The story centers on Tripp (Lucas Till), a high school student who appears to be the oldest high school student in his purported North Dakota hometown, where mountains are tall and numerous and where you can escape to stunning tree-filled slopes. Anyway, the restless Tripp finds solace working on pickups at the junkyard, but he gets a jolt when a creature — a cross between Jabba the Hutt and Jaws, only more cuddly — shows up at the workplace, having escaped the evil capitalists at the fracking plant.

Director Chris Wedge imbues these beginning scenes with a nice level of suspense, reminiscent of the early moments of “E.T. the Extra-Terrestrial,” the movie that “Monster Trucks” wants to emulate. But “Monster Trucks” is no “E.T.”

Perhaps most important, the crucial relationship between Tripp and the creature falls flat, and any chance of any emotional investment is thrown off the dashboard when the story focuses on the amalgamation of the creature with the truck. The monster-in-the-truck adventure makes for a decent set-piece, much like the flying bicycle moment did in “E.T.,” but it does not a movie make. As things progress, we don’t really care what happens to Tripp, who has the same expression whether he’s facing the monster, dangling off a cliff, or wooing the girl next door.

Fortunately, Wedge knows how to pace things — and can stage a solid chase scene — so “Monster Trucks” feels less like an ordeal than a well-intentioned misfire made by intelligent people. This is a movie for kids, and the best of this fare straddles the line of relating to children and being sophisticated enough for adults. This is a film that, in some ways, is too complex for the kids, yet still leaves the adults feeling left out, too.