“Babylon A.D.” is one of those rare cases where the old storytelling maxim about showing instead of telling just doesn’t apply. The movie shows us a lot—mostly Vin Diesel shooting bad guys, choking dudes to death and taking on unmanned spy planes—but it doesn’t tell viewers a damn thing. It’s a big, dumb cipher, a puzzle with half the pieces missing and explosions thrown in to fill in the blank spaces. There’s promise in there, somewhere, and maybe “Babylon A.D.” will get rehabilitated a few months from now when it comes out on DVD with all the missing scenes restored. As it is now, though, the movie is an incoherent mess that takes a half-hearted stab at solid sci-fi world building.

At the center of all the gunfire, missiles and car chases is Toorop (Vin Diesel), a soldier-turned-mercenary living out his days in a run-down apartment in Russia. It’s the future, and some sort of vaguely defined disaster has occurred, with refugees living on the streets and trying to eke out a living by selling guns and dead rabbits. Everyone’s wearing cammo, too, so you know things are really bad.

Toorop is thrown back into the mercenary life when corpulent gangster Gorsky (Gerard Depardieu) recruits him to deliver a young girl named Aurora (Melanie Thierry) and her guardian, Sister Rebeka (Michelle Yeoh), to America. Gorsky doesn’t say why, and Toorop doesn’t ask, and before long, Toorop and the two women are fighting off attackers, climbing around rogue submarines and riding snowmobiles on their trek from Russia to America. Aurora, of course, has a secret, and her mysterious parents are determined to reclaim her for their own ends. Predictably, once all the gunfire stops and the fires are put out, the cynical, jaded Toorop learns how to love. And some sort of messiahs may or may not have been born.

An adaptation of the French sci-fi novel “Babylon Babies,” “Babylon A.D.” cribs heavily from “Children of Men” and “The Transporter,” with a dash of “The Fifth Element” thrown in. But “Babylon” doesn’t have the intelligence or emotional resonance of “Children of Men,” the kinetic action of “The Transporter” or the campy, sort of good-natured spirit of “The Fifth Element.” It’s a ponderous affair weighed down with an unearned self-importance, and even when Diesel is kicking ass, the movie feels like a chore. In a way, it is—trying to keep up with the plot of “Babylon A.D.” is exhausting, and while director Mathieu Kassovitz maintains that much of the plot ended up on the cutting room floor, it’s hard not to imagine a few extra minutes of footage would have cleared things up.

Some of the pieces are in place, and the movie’s production design, by Paul Cross and Sonja Klaus, gets close to the sort of gritty aesthetic in “Children of Men.” Some parts, like the refugee camps in Russia and Toorop and Aurora’s mad dash for a secret submarine, have a unified look and style about them; other parts, such as an airplane emblazoned with a Coke Zero logo, feel lazy and derivative.

By comparison, the world of “Babylon A.D.” is supremely fleshed out when contrasted with the story. The world is apparently run by theocratic corporations, all competing with each other for converts. This is an intriguing bit, but like the rest of the film, it’s one that’s left unexplained and unexamined.  Aurora is supposed to be some sort of genetically engineered messiah—or maybe not. By the end of the movie, any sort of logic is abandoned. Charlotte Rampling gets a few scenes as the High Priestess, the CEO of one of these capitalist theocratic cabals, but she’s mostly wasted. Really, the whole cast is wasted here. Even Vin Diesel, who can partly thank moody sci-fi flicks for his career, isn’t even trying here. He gives a lazy smirk, shoots someone, grumbles a few lines and moves on.

Prior to the film’s release, Kassovitz  offered some surprisingly candid critiques of the movie, blaming Twentieth Century Fox for butchering the film during the editing process, making it “stupid” without the “metaphysical point of view” the film was supposed to have. Kassovitz is right—“Babylon A.D.” sure isn’t smart, but its philosophical credentials aren’t up to snuff, either, and it’s unlikely a special-edition DVD will fix the film’s biggest problem: an inflated sense of self-importance. Kassovitz might have been better sticking with the action and forgeting the god stuff. When confronted with the choice between hubris and excessive explosions, always go for explosions—they never disappoint.