Under 30,000 feet of water, the experimental exploration rig Leaguer has discovered an oil field larger than Saudi Arabia, with oil so sweet and pure, nations would go to war for the rights to it. But as the team starts drilling exploration well after exploration well in their race to claim the sweet crude, a deep rumbling beneath the ocean floor shakes them all to their core. Something has been living in the oil and it's about to give birth to the greatest threat humanity has ever seen.

When an earthquake strikes downtown Denver, far from the nearest active fault system, the USGS dispatches Dr. Dayna Raines and an emergency response team to investigate. They discover that the epicenter corresponds to a decommissioned deep injection well once used by the U.S. Army to dispose of chemical weapons, which have eroded the earth and created the unstable cavern system responsible for the seismic activity.

On a desolate beach in far northern Scotland, the winter storms have been washing up all manner of things since time began. But buried in the centre of one smaller iceberg is a shard of ancient Viking pottery telling a partial tale of a hidden mysterious island beyond the ice and mist, that was home to a great treasure and even greater horrors. Thawing in the same block of ice was a rotting flap of skin that refused to be identified but had similar skin patterns to a creature not seen for 100 million years.

A bizarre series of incidents take place on a usually tranquil lake. Boats are found ravaged, a body torn in two, other people are missing and an injured victim cries of a monster. Chief of Police Morgan Sydney must face the reality that a huge monster is lurking in the lake. With bulletproof scales, territorial aggression, and an insatiable appetite, the beast causes mayhem in the peaceful town.

A chain of subglacial volcanoes erupt in Iceland. The melting ice floods the countryside. Poisonous gas descends on Scotland. A tsunami devastates the Norwegian coastline. An ash cloud rises into the atmosphere, blotting out the sun across Europe, ushering in a new Ice Age. Dozens of nuclear power plants, flooded by ocean water, experience meltdowns. Millions perish. Many more are displaced. All on the first day.