Deep below the surface of the Pacific Ocean, the prehistoric predecessor of today's great white shark still thrives: the Megalodon, a 60-foot, 20-ton monster. Professor Jonas Taylor is the only man to have survived an encounter with the beast, and the only person adamant that the Meg is still in existence. But when several deep sea probes are disabled in the area where Taylor claims to have seen the Meg, he is called in to investigate. Now Taylor must face his second encounter with the beast--and only hope and quick wits will keep him alive.