Deep Blue Seais a 1999 science fiction horror film that stars Thomas Jane , Saffron Burrows , LL Cool J , and Samuel L. Jackson . The film was directed by Renny Harlin and was released in the United States on July 28, 1999.

On Aquatica, a remote former submarine refueling facility, a team of scientists are searching for a cure for Alzheimer's disease . Dr. Susan McAlester ( Saffron Burrows ), violates a code of ethics (the fictitious "Harvard Genetics Compact"), and genetically engineers three Mako sharks to increase their brain capacity so their brain tissue can be harvested as a cure for Alzheimer's. The increased brain capacity makes the sharks smarter, faster, and more dangerous. Aquatica's financial backers become skeptical about the tests and send a corporate executive ( Samuel L. Jackson ) to visit the facility.

To prove that the research is working, the team manage to remove brain tissue from the largest shark. The shark attacks a scientist, and as he is put into a helicopter to be flown to land, the helicopter crashes as the sharks attack it. A shark breaks the glass of the underwater laboratory by ramming it, flooding the lab and letting the sharks inside the facility. The group has to escape the sinking research center and avoid being killed as the sharks begin targeting the scientists as prey.

The team is slowly killed off by the sharks as they climb to the top of the facility, but during the journey, the cook, Preacher ( LL Cool J ) manages to kill the first shark by setting the kitchen on fire by igniting the natural gas supply; also, Dr. McAlester kills the second shark by electrocuting it while unsuccessfully trying to retrieve her data from her room. With the first two sharks dead, Dr. McAlester, Preacher, and Carter Blake ( Thomas Jane ) ascend to the top of the building. They discover that the sharks want to escape into the open sea, but they decide that they cannot let that happen, as the sharks will breed with other sharks.

Dr. McAlester, in a effort to distract the the third and final shark, cuts herself and dives into the water, while she attempts to get back to land the ladder crumbles and breaks, she is then devoured by the shark. Her death lures the shark into a position where Preacher and Blake are able to kill it by shooting it with a wire attached to a harpoon and connecting it to battery, causing the shark to explode. With all three sharks now gone, Preacher and Blake wait on top of the flooded facility as they see boats containing other researchers arriving.