Samual L Jackson plays a businessman who sinks $200 million into a special project to help fight brain cancer. As part of this project, medical biologist Susan McAlester (Saffron Burrows) rather naughtily figures out a way to genetically embiggen shark brains, so that cancer-battling enzymes can be harvested. However, the shark subjects become super smart and decide they dont much like being cooped up in pens and being stabbed with hypodermics, so they figure a way to break out and make for the open sea.