Aquatica is a research lab located in the ocean. Doctor Susan McAlester and Doctor Jim Whitlock are currently doing research to help in the re-activation of dormant human brain cells like those found in Alzheimer's Disease patients. It seems that sharks do not lose any brain activity as they age, leading Susan and Jim to think that the proteins found in the sharks' brains may lead to a cure for Alzheimer's Disease, which is what killed Susan's father. The research is being funded by a group of investors headed by Russell Franklin, and the investors are getting impatient with the pace of the research. It doesn't help that a shark got loose from Aquatica, and attacked a few teenagers who were on a pleasure romp. In an effort to save her project, Susan gets a forty-eight-hour reprieve from Russell, who goes to the Aquatica to see how his money is being spent. Susan skips a few steps in the research project and genetically re-engineers the DNA of three mako sharks in order to create larger makos so the makos will have larger brains. With only her weekend skeleton crew on board -- that is, marine biologist Janice Higgins, engineer Tom Scoggins, shark expert Carter Blake, meteorologist Brenda Kerns, and Aquatica chef Sherman "Preacher" Dudley -- Susan prepares for her experiment. The test is successful, but then they all see what Susan's genetic re-engineering on the sharks has done -- one of the sharks wakes up from an anesthetic and kills Jim. Susan and her crew radio for help, and a rescue helicopter crashes into the station during a tropical storm, and then another shark attack leaves Aquatica sinking into the water. The surviving crew members do whatever they can think of to escape from Aquatica while they're trying to fight off the three sharks.