It isn't that James Cameron's docudrama "Ghosts of the Abyss" is bad. It's just there, complete with the pretentious excess of "Titanic" (also by Cameron). Bill Paxton narrates and, in effect, stars in this chronicling of a trip to the bottom of the sea that has no real purpose save to flog the wreck of the Titanic, Cameron's cash cow.

All in IMAX 3-D.

The IMAX format is like a talking dog. What that dog has to say isn't really as important as - dude ... it's a talking dog. IMAX 3-D is like a talking dog that also dances the mambo - a gimmick so dazzling that you aren't supposed to notice the dog doesn't have rhythm and speaks with a lisp. And so it is with "Ghosts of the Abyss," a film that lacks focus both on and off screen. (The 3-D has an irritating doubling artifact that continually makes you take your glasses off to check them.)

Here's the drill: Paxton and a deep-sea exploration group will send these remote-controlled cameras through the wreckage of the Titanic. Why? Why not? One scientist is interested in "rusticles," the deep-sea life steadily eating away at the Titanic. But the sole purpose of this trip seems to be so that this movie, which becomes a missed opportunity, could be made.

Look, you've got cameras in the wreck of the Titanic. We should get images from beginning to end. The ones that we do get are neat, like the intact leaded glass windows, or a man's bowler hat that is sitting exactly where he left it.

Paxton's dialogue swings between goofy - "It was spooky," he says of his voyage 12,500 feet below the ocean's surface - and melodramatic as he relates the voyage of a scientific crew you don't care about to a wreck that they really don't show you enough of. We want to see more of the wreckage, darn it, not the exploration crew playing volleyball.

All this hooey is interspersed with computerized reenactments that place actors playing Titanic guest and crew members among the wreckage. The band is sawing away on the deck of this watery grave, sailors help people into lifeboats - ghostlike computer images that are supposed to enhance your understanding and compassion. They don't. They're kooky.

"Ghosts of the Abyss" reaches its nadir as one of the remote-controlled cameras, Elwood, runs out of power while in the wreckage. Jake (get it? The Blues Brothers) comes to his rescue, but so what? It's a camera. Buy another one.

The rescue works, to the strains of "Just the Two of Us," and all you want to do is get your baseball bat and have at the person responsible for this pretty-but-empty clunker.

Turns out that Elwood is rescued on Sept. 11, 2001. Yes, that Sept. 11. But the crew decides to carry on like troupers in the task to bring us nothing at all, really.

There are some nice shots of the wreckage, once you get past your ire at being manipulated by 3-D cliches like things coming at your face, or underwater shots of boats, for no other reason than "dude, that rocks." But, ultimately, this talking dog don't hunt.