The film is inspired by the idea of a global doomsday event coinciding with the end of the Mayan Long Count Calendar’s current cycle on or around December 21, 2012 (the northern hemisphere’s winter solstice).

Jackson Curtis (John Cusack) is a divorced father who occasionally works as a limousine driver and a writer, while his ex-wife Kate Curtis (Amanda Peet) and children live together with her new boyfriend. In Guatemala reports start coming in of mass suicides in the Mayan jungles of people attempting to avoid the impending apocalypse.

The IHC (Institute for Human Continuity), a secret organization, has realized the situation and begins constructing vast arks beneath the Himalayan mountains designed to withstand most natural disasters in order to save both humanity, significant species, and the greatest treasures of mankind for when doomsday finally happens.

There are arguments however about how and when the governments of the world will alert their fellow citizens and even discussions about how the remaining survivors will be selected to survive Armageddon, but when they discover that the global cataclysm is happening much faster than expected, they must race to these ships to save the human race before all is lost.

Meanwhile on a day trip to Yellowstone with his two young children, Jackson meets Charlie Frost, who hosts his own radio segment and blog about his belief that the Mayans are correct about 2012.

Over the coming days vast cracks are found within the fault lines in California, and despite the pleas from the government that everything is fine, Jackson isn’t convinced. Hiring a private plane and gathering crucial supplies he races to Kate’s home to save himself and his family from the Earth’s crust displacement occurring all around them.

After a long and dangerous race through the collapsing streets to get to the Santa Monica Airport, Kate’s new boyfriend Gordon (Thomas McCarthy) uses his pilot skills to get the family to safety as the runway crumbles beneath them. After they take off, they fly dangerously through Los Angeles as the entire city collapses into oblivion. As they look back, the entire cityscape has already started to crumble into the Pacific.

It soon becomes clear that it’s not just California that’s experiencing disaster. The Yellowstone Supervolcano erupts, Las Vegas is destroyed by a massive chasm that cuts through the Strip and by an ash cloud from the Yellowstone eruption, massive earthquakes began to occur in South America (destroying the cities of Rio de Janeiro and Buenos Aires), Washington D.C. is flooded by an enormous tsunami in which the USS. John F. Kennedy crushes the White House and St. Peter’s Basilica in Rome crumbles into oblivion, killing thousands of people in prayer. As massive tidal waves began to sweep across the Earth (even at one point beginning to climb over the Himalayas), the U.S. government declares the end of the world.

A group of survivors, including Jackson and his family, must fight their way to China before they can board the great arks and save themselves from the gigantic tidal waves flooding the Earth.