In the cold South Pacific waters off the coast of New Zealand, a team of divers and scientists are preparing for three days in a specially designed habitat 1300 feet below the surface. In this alien and savage world, the mysterious great white sharks gather to hunt and to breed. When the dive team's only link to the surface is destroyed, they find themselves in a desperate battle for survival. With the air running out, and no hope of rescue, they must use their wits to survive against sharks, each other, and a terrifying nightmare of legend.