Barreling along 100 feet beneath the surface, the giant predator gained swiftly on its prey. Fifty yards ahead, a school of chrome-colored fish fled terror-stricken before it. Measuring close to 20 feet in length, the enormous descendants of the prehistoric fish Xiphactinus audax were, themselves, top predators, each tipping the scales at over 3,000 pounds. Compared to the whale-sized nightmare that pursued them, however, the toothy, tarpon-like creatures were little more than a snack.

Nestled off the coast of Cuba and shielded by impenetrable reefs of razor-sharp rock, stands Diablo Caldera. To the rest of the world, the extinct, bowl-shaped volcano is hardly worth exploring. But the caldera has a secret. Its isolated saltwater lake has remained untouched since the fall of the dinosaurs.

Inside this hellish aquarium are the deadliest marine predators the world has ever seen. Imprisoned behind towering walls of volcanic rock since the Cretaceous, and warded by a mysterious race, Diablo's savage inmates rule with flipper and fang the only world they have ever known.

But something is about to change. The prison that is Diablo is beginning to fail, and soon it will unleash into the unsuspecting Atlantic a primeval fury the likes of which it has never before known.

It is 100 tons of death. And it likes to eat.