At 1:01 A.M. Greenwich Mean Time on December 11, 1999, computer systems all around the globe freeze for twenty seconds, then return to normal. Susan Garnett, a senior analyst at the FBI's high-tech crime unit, scours the nation's networks for a virus that could have triggered the synchronized event. But her search yields only indecipherable code. The next day, nineteen days before the end of the millennium, at the exact same time, the freeze happens again - for nineteen seconds.

The virus is counting down to the year 2000, when the world's computers will be at their most vulnerable point in history. Susan traces the virus's signal to its point of origin, an area near Tikal, the site of one of the largest and most advanced cities of the ancient Maya. How can such an advanced virus originate from a primitive region of the world? What type of global event will the virus trigger at the turn of the millennium?

Certain that the answers are hidden in the densely packed jungles of the Yucatan Peninsula, Susan convinces the U.S. government to allow her and Cameron Slater, an anthropologist who has studied the Maya extensively, to travel to this remote region in a last-ditch effort to stop the countdown.