The movie is basically about a four people who find a crashed drug smuggling plane on the ocean floor while diving and then decide to recover it and sell the profits. This of course leads to problems when they try to inadvertently sell it back to its owner, who of course takes umbrage and threatens to kill them.
The first 2/3 of the movie is only six pack abs and good looking people in tiny bikinis, swimming underwater. Don't get me wrong, I appreciated Jessica Alba as much as anyone, but a good story and some adequate pacing would have been nice.
The story doesn't really pick up until after they recover some of the drugs, and by then, most viewers will be bored. The last third of the movie has the usual sharks, guns, and bad boys doing bad things. My advice is to wait until it's in second run or on DVD.