They forgot to empower the script

Fantastic is a tough adjective to live up to and “Fantastic Four” takes its best shot, but it fails to be anything more than a mild summertime diversion. Based on the Marvel comic book, it’s a prototypical air conditioner movie -- it’s probably only worth 10 bucks if your apartment is really, really hot or if you’re a Jessica Alba completist.

More superhero sitcom than comic book adventure, the movie lacks a strong, dramatic through-line. It’s a series of connected, angst-ridden subplots that don’t add up to a feature film. Director Tim Story ably moves things along but never succeeds in making the sum greater than its parts. Though their powers may be super, these characters are way too self-involved to be heroic.

“Fantastic Four” dives quickly into the story of scientist Reed Richards (Ioan Gruffudd, TV’s Horatio Hornblower) and his astronaut-sidekick, Ben Grimm (“The Shield’s” Michael Chiklis), as they warily approach their archrival, billionaire industrialist Victor Von Doom (Julian McMahon of “Nip/Tuck”) to fund a space mission in which they plan to unlock secrets of human genetics. Once a deal is struck, they’re quickly joined on the interstellar flight by Von Doom’s director of genetic research, Sue Storm (Alba), and her hotshot NASA dropout brother Johnny (Chris Evans).

The cosmic storm Reed sought to explore for his research arrives early, causing an accident that exposes the crew to dangerous amounts of radiation. Back on Earth they quickly recover from their injuries but begin to display what might understatedly be referred to as side effects.

Johnny exhibits a tendency to burst into flames, Sue becomes invisible when emotionally engaged, and Reed develops the elasticity of silly putty. Though these “gifts” come and go, Ben is saddled with a more permanent affliction: His body has mutated into a mass of solid, rock-like material that gives him super strength but makes him a little hard to look at. Director Story and screenwriters Mark Frost and Michael France nimbly present the symptoms following the accident and then wittily demonstrate the relationship to each character’s personality. The audience is always a step ahead of the jokes, but the recognition is part of its fun.

Rock star celebrity follows as the Human Torch, the Invisible Woman, Mr. Fantastic and the Thing, as they are soon tagged by Johnny, are forced to face Brangelina-size paparazzi and fan attention, as well as the threat of Von Doom, who undergoes a startling physical transformation of his own. The filmmakers have some fun spoofing the drawbacks of unwanted fame, but that thread tends to exemplify the problem the film has in deciding if it wants to be “Ghostbusters” or “X-Men.”

These aren’t necessarily warring sensibilities, and a more skillful execution would have elevated “Fantastic Four” to another level of comic-book movie. The filmmakers seem to have been straining for a more complex hybrid genre -- one in which the humor and action serve the story equally -- than they were able to deliver. As is often the case with big-budget action movies, the central story is simply not strong enough to support the ambition.

The mishmash of stories is as hit-and-miss as the film’s many gags. Johnny embraces his new powers, even trying to expand upon them by learning to fly, and Evans leaps into the part with bravado and gets most of the script’s best lines. Chiklis projects a big hunk of humanity through layers of prosthetics as the Thing, and McMahon is suitably despicable as the preening villain. The chemistry between Gruffudd and Alba, however, as the supposed love interests, recalls a DC Comics character -- Mr. Freeze.

“Fantastic Four” works best during its first half establishing the alliterative quartet’s super powers after the accident transforms their DNA. Once that’s established, the movie loses its way and it becomes clock-watching time. Still, Story, who directed “Barbershop,” is surprisingly adept at handling the action sequences and special effects, most of which are excellent.

The Fantastic Four were originally created in the early 1960s as dysfunctional superheroes in contrast to the more idealized heroes previously seen in comics and pop culture in general. The filmmakers have picked up on that, continuing the in-fighting and tendencies to screw up. Ultimately, they aren’t trying to save the world, they’re merely trying to save themselves. It’s a lesson in self-acceptance and a metaphor worthy of Dr. Phil, but it isn’t all that entertaining.

*

‘Fantastic Four’

MPAA rating: PG-13 for sequences of intense action, and some suggestive content.

Times guidelines: Violence is strictly comic book, sensuality is tepid.

Jessica Alba...Invisible Woman

Michael Chiklis...The Thing

Chris Evans...Human Torch

Ioan Gruffudd...Mr. Fantastic

Julian McMahon...Dr. Doom

A 20th Century Fox release. Director Tim Story. Producers Bernd Eichinger, Avi Arad, Ralph Winter. Executive producers Stan Lee, Kevin Feige, Chris Columbus, Mark Radcliffe, Michael Barnathan. Screenplay Mark Frost and Michael France, based on the Marvel comic book by Stan Lee and Jack Kirby. Director of photography Oliver Wood. Editor William Hoy. Music John Ottman. Costume designer Jose I. Fernandez. Production designer Bill Boes. Running time: 1 hour, 45 minutes.

In general release.