Following the inevitable prologue in which two young couples on a small boat are attacked, the film wastes no time in introducing Dr. Susan McAlester (Saffron Burrows), a marine biologist, who convinces her corporate funder, Russell Franklin (Samuel L. Jackson), to come back with her to her research lab on a former U.S. Navy sub base, to prove that she has found a potential cure for Alzheimer's disease, involving three 45-foot test sharks that move at an alarmingly swift pace and who are unusually smart. With most of the staff leaving for the weekend, Susan, Russell, and six additional workers, including co-creator Carter Blake (Thomas Jane); engineer Tom Scoggins (Michael Rapaport); chef Preacher (LL Cool J); and assistants Janice Higgins (Jacqueline McKenzie) and Jim Whitlock (Stellan Skarsgard), are left alone. When a violent storm arises and, through a series of circumstances, the base is severely damaged and partially flooded, the three sharks swim on-board to terrorize the inhabitants, all of which are underground with very little means of being able to reach the surface.

The plot of "Deep Blue Sea" certainly isn't going to win any award for inventiveness, as the same basic premise and set-up has been remade too many times to count, but luckily, Harlin revs the film up surprisingly quickly after all of the characters are introduced, and afterwards, is so relentless on its action scenes that you rarely get time to take a breather. And just when you think you can, there will be a startling jolt to put you right back on the edge.

Since there really isn't anything new to be done with this type of movie, and thus, they almost always end up being a bore (see 1998's "Deep Rising" and 1999's "Virus"), "Deep Blue Sea" demonstrates that any film's success depends solely on its treatment and expertise, which Harlin has always been known for. In an attempt to compel and arouse the viewer, Harlin does not skimp in any way on energy, nor could he ever be accused of making a "boring" film (unless, of course, it's name happens to be "Cutthroat Island"). Once the storm hits, the first victim is dispatched in an elongated, grisly manner, and the ball gets rolling approximately thirty minutes in, the movie doesn't let up, with a big action setpiece arriving every few minutes. Most directors would simply present a "death" scene, juice it up with middling suspense, and then move on to the next scene, but with Harlin, he always seems to take the action, and intensity, one step further (as in 1993's "Cliffhanger" and 1996's "The Long Kiss Goodnight") so as to amaze and entertain with his particular creativity.

One other compliment that must be made is that, more than any horror-style picture of its type in awhile, the proceedings are often unpredictable when dealing with who the victims will be. Usually you can tell, with the top-billed actors living, and the lesser-known supporting players being offed, but this tried-and-true formula is promptly crumpled up and thrown away as one of the "main" characters is unexpectedly torn to shreds midway through. Once this vital moment occurs, you realize no character is safe, similar to the now-infamous Drew Barrymore opener in 1996's "Scream."

Dodging the utter corniness of the derivative "The Haunting," "Deep Blue Sea," like all of its similar predecessors, still remains weak on the screenplay level. Written by Akiva Goldsman (who destroyed the "Batman" series with 1997's horrendous "Batman and Robin"), the film leaves something to be desired when reminiscing back on the dialogue and one-note characters. Despite being played straight most of the time, Goldsman foolishly feels the need to sprinkle one-liners here and there, every single one of which falls as flat as a pancake. The characters aren't much better (actually they're worse). In the course of the film, you are lucky to learn much of anything about the humans, as they are mostly there as pawns in a far bigger chess game and are given very little time to develop substantially satisfying individual personalities. The actors do what they can, however, and are mostly so believable that it would be rather easy to overlook the needlessly underwritten characters. Of them all, LL Cool J is given the most time to really shine (and is also the most likable), while Saffron Burrows and relative newcomer Thomas Jane act as the heroine and hero, respectively. Also of notice is Jacquelyn McKenzine, an obvious character actress (just watch her heartwrenching turn in 1997's Australian drama, "Angel Baby"), who is highly empathetic and given the most effective scene, not to mention a supreme example of raw terror (only surpassed this year by "The Blair Witch Project"). Unfortunately, it is the most seasoned pro, Samuel L. Jackson, that doesn't seem to be in his usual top form, but that probably has something to do with his poorly-written role. As for the sharks, the mechanical ones are more plausible than the CGI ones, but aren't as awe-inspiring on a visual level. Both types, however, achieve satisfactory villain status.

All in all, "Deep Blue Sea" is neither deep nor meaningful. It knows it is a popcorn movie, pure and simple, but unlike most of them that leave you feeling even more hungry than when you first sat down to watch the film, this movie, indeed, gives you the much-needed bang for your buck. Go in expecting a masterpiece of modern cinema, and you are surely setting yourself up for a disappointment. But go in expecting to be genuinely entertained, and you'll have yourself a rollicking time. Besides, what was the last high-profile summer action movie that even succeeded on this most elementary level?