On an island research facility, Dr. Susan McAlester (Saffron Burrows) is harvesting the brain tissue of DNA-altered sharks as a possible cure for Alzheimer's disease. When the facility's backers send an executive (Samuel L. Jackson) to investigate the experiments, a routine procedure goes awry and a shark starts attacking the researchers. Now, with sharks outnumbering their human captors, McAlester and her team must figure out a way to stop them from escaping to the ocean and breeding.