When 17 people suddenly drop dead within a 10-block radius in Boston, geophysicist Dr. Josh Keyes and French atomic weapons Dr. Serge Leveque are summoned by General Thomas Purcell to Washington, D.C. to find out if the deaths are due to a covert enemy electromagnetic weapon. When it's determined that this was not an act of war, the government breathes a sigh of relief and the scientists are dismissed.
But Keyes can't let go of the deaths so easily, and when other bizarre "natural" phenomena begin occurring worldwide, he suspects the earth's electromagentic field has been compromised. Working with his team at the University of Illinois, Keyes discovers the mystery behind the strange occurrences is more frightening than any act of war. For reasons unknown, the earth's inner core has stopped rotating, causing the planet's electromagnetic field to rapidly deteriorate. At the same time, life as we know it begins deteriorating as well, causing birds to lose their ability to navigate, whales to erratically change their migration patterns and people with pacemakers to suddenly drop dead. Even the famed Northern Lights appear in the night sky a hundred times brighter and farther south than ever before.
And things will only get worse. As the electromagnetic field, which shields the earth from solar radiation, slowly collapses, airplanes will start falling from the sky and everything electronic will be fried. Static discharge in the atmospehere 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, an arrogant scientist who at first is disbelieving, but soon arrives at the same horrifying conclusion. Soon the two men, along with the atomic wepons specialist Leveque, are whisked away by federal agents to the Utah desert to meet Dr. Ed "Braz" Brazzelton, a brilliant scientist who has been working for the last 20 years on a craft that can travel deep into the earth some day. But with no more time to research, and with money suddenly no object, the U.S. government and the United Nations rally together to create a team of world experts that will build a fully functional subterranean craft -- immediately. And, because Keyes and his colleagues are scientists, not pilots, astronauts Rebecca "Beck" Child and Colonel Robert Iverson are recruited to become the world's first "terranauts."
With their hastily built ship and their highly skilled, wildly diverse team of professionals to man it, the government and the world make the ultimate leap of faith ... not into outer space, but into inner space, journeying into unknown regions of the earth in hopes of detonating a nuclear device they hope will reactivate the core and restore balance to the planet.