‘Are you saying we opened up a superhighway for giant sharks?” someone asks in the course of “The Meg.”

That’s some ridiculously bad dialogue, but I would argue that “The Meg” needs more of this kind of thing. This giant-shark opus isn’t too serious, but it isn’t tongue-in-cheek enough either. It’s neither fish nor completely (sorry) foul.

The answer to the superhighway question is pretty obvious. When a science-research team punctures a hole in the heretofore-unknown layer of hydrogen something-or-other at the bottom of the Mariana Trench, it allows hidden creatures to swim out.

Awkwardly, these creatures include the megalodon, a giant prehistoric shark (which really existed), a beast with a tendency to attack vehicles carrying humans. The humans are led by Jason Statham, as a submersible pilot who’s trying to get over a previous deadly undersea incident, after which nobody believed him about the giant prehistoric shark down there.

There’s also a scientist (Winston Chao), his eligible scientist daughter (Chinese superstar Bingbing Li), the billionaire funding this project (Rainn Wilson), and various techies (Page Kennedy and future “Batwoman” Ruby Rose). Not a bad bunch to be around, even if the characters are wading-pool-deep.

If a shark really has to keep moving or else it dies, then director Jon Turteltaub, who did the “National Treasure” movies, wisely keeps this thing going. We sprint from the Mariana Trench to open water to the research station to a Chinese beach, where the Meg can make a meal of thousands of extras. The film was largely financed with Chinese money, which might explain the emphasis on Asian actors and locations.

The script labors to make the pieces fit together. But the tone keeps wavering — one minute we’re mourning the dead, the next minute the “I gotta get a new job” jokes are flying.

Also, it bugged me that the research station has to be manned by dozens of unnamed characters. A movie like this is best when it’s a tight little group fighting a monster. I kept wondering what those other people were doing at the station (other than thinking “I gotta get a new job”).

Give the movie credit for a few hair-raising escape scenes, including the moment the Meg starts swallowing a plexiglass shark cage with Bingbing Li still inside it. I also enjoyed Statham riding the giant shark while plunging a harpoon into it, like an action-hero Captain Ahab.

Statham stays pretty expressionless throughout, which allows him to keep his dignity. This includes his scenes with Li’s little daughter, which ought to please the children in the audience as they wait between the terrifying scenes of a giant-toothed shark eating people.

There’s a way to make dumb movies fun — let me remind you of “Skyscraper,” if I may. But “The Meg” isn’t savvy enough to hit those notes, and with its charisma-free villain (the computer-generated Meg has zero physical presence), the movie evaporates before your eyes.

“The Meg” (2 stars)

Jason Statham and his crew do battle with a giant prehistoric shark, in a movie that isn’t too serious but isn’t tongue-in-cheek enough either. Director Jon Turteltaub wisely keeps the action moving, but the movie is sunk by the uncertain tone and the charisma-free computer-generated villain. With Bingbing Li, Rainn Wilson.

Rating: PG-13, for violence

Opening: Alderwood, Alderwood Mall, Everett Stadium, Galaxy Monroe, Cinebarre Mountlake Terrace, Marysville, Stanwood Cinemas, Meridian, Oak Tree, Pacific Place, Seattle 10, Thornton Place, Woodinville, Blue Fox, Cascade Mall, Oak Harbor Plaza