Dr. Susan McAlester's experiments are on the verge of creating medical history. But to reach her goal, she has violated ethical codes, genetically re-engineering the DNA of mako sharks. One of nature's most lethal killing machines has become more useful to her research, but also more intelligent and powerful in the process. But McAlester has more to worry about than the deadly specimens at the center of her studies. Her questionable methods put a strain on the relationships with her fellow team members, chiefly shark expert Carter Blake. Compounding the tense atmosphere, Aquatica's financiers are skeptical and nervous and have threatened to shut down the off-shore facility on the eve of a round of Dr. McAlester's key tests. Russell Franklin, the leading backer, has been dispatched to Aquatica to deliver an ultimatum - the research must prove conclusive, or funding is revoked. Susan and her team successfully extract brain tissue from the largest of the mako sharks. But a tragic accident during the procedure sets off a chain of events that results in irreparable damage to the research facility. With a tropical storm swirling around the now sinking Aquatica, the scientists and workers find themselves stalked by the new generation sharksfighting against the deadly man-made forces of nature they helped to create.