In the insatiable quest for natural resources, humans are searching further and deeper into the earth, threatening to unleash monsters thought to be long gone. The megalodon, the prehistoric ancestor of the great white shark was the most ferocious predator of the seas, an 80 foot killing machine extinct for millions of years… But when divers drilling in an underwater cave are attacked by this living fossil, oceanographer Kim Melville discovers that this creature may not only have survived, but thrived, and is reclaiming its place at the top of the food chain.