For reasons unknown, the earth's inner core has stopped rotating, causing the planet's electromagnetic field to rapidly deteriorate. Instantly, life around the globe begins to change dramatically. In Boston, 32 people with pacemakers, all within a 10-block radius, suddenly drop dead. In San Francisco, the Golden Gate Bridge collapses, sending hundreds of people plunging to their deaths. In London's Trafalgar Square, flocks of pigeons lose their ability to navigate, flying into panicked crowds, slamming into windshields and causing drivers to lose control of their cars. And in Rome, as thousands of tourists watch helplessly, an electrical superstorm reduces the ancient Roman Colosseum to rubble.
Scrambling to resolve the crisis, government and military officials call upon geophysicist Dr. Josh Keyes (Aaron Eckhart) and a team of the world's most gifted scientists to travel into the earth's core in a subterranean craft piloted by "terranauts" Major Rebecca "Beek" Childs (Hilary Swank) and Commander Robert Iverson (Bruce Greenwood). Their mission: Detonate a nuclear device that will reactivate the core and save the world from sure destruction.
When unexplained catastrophes strike around the globe, geophysicist Dr. Josh Keyes (Aaron Eckhart) and French atomic weapons expert Dr. Sergei Leveque (Tchey Karyo) are summoned by General Thomas Purcell (Richard Jenkins) to Washington, D.C., to determine if covert enemy action is to blame. Working with his team at the University of Illinois, Keyes discovers the mystery behind the tragedies is more frightening than any act of war -- the earth's inner core has stopped rotating. As a result, the planet's electromagnetic field, which shields the earth from deadly solar radiation, is collapsing. If the problem is not resolved quickly, airplanes will start falling from the sky and everything electronic will be destroyed. Static discharge in the atmosphere will create "super-storms" with hundreds of lightning strikes per square mile, and deadliest of all, microwave radiation will literally cook the planet.
Terrified by his findings, Keyes seeks out the opinion of renowned geophysicist Dr. Conrad Zimsky (Stanley Tucci), an arrogant scientist who arrives at the same horrifying conclusion. Together, they determine that the only way to reactivate the core is to travel to it. But how? Man has walked on the moon and landed on Mars, but never has anyone dared to explore the inner, deepest regions of the earth ... until now.
Living in a remote area of the Utah desert, a brilliant scientist, Dr. Ed "Braz" Brazzelton (Delroy Lindo), has developed an untested subterranean craft that they hope will be able to penetrate deep into the earth, even as far as the core. Now it is up to Keyes, a team of scientists and astronauts Major Rebecca "Beck" Childs (Hillary Swank) and Commander Robert Iverson (Bruce Greenwood), who have just been recruited as the world's first "terranauts," to drive this high-tech vessel into the earth, detonate a nuclear device and somehow restore balance to the planet. It's the ultimate leap of faith ... not into outer space but into inner space, a journey into an unknown frontier where truly no man has gone before.