While James More is held captive by terrorists in Somalia, thousands of miles away on the Greenland Sea, his lover Danny Flinders prepares to dive herself in a submersible into the deep bottom of the ocean, tormented by the memories of their brief encounter in France and her inability to know his whereabouts.
A deep-sea submersible, part of an international undersea observation program, has been attacked by a massive creature, previously thought to be extinct, and now lies disabled at the bottom of the deepest trench in the Pacific with its crew trapped inside. With time running out, expert deep sea rescue diver Jonas Taylor is recruited by a Chinese oceanographer to save the crew – and the ocean itself – from this unstoppable threat: a pre-historic 75-foot-long shark known as the Megalodon.