Fasten your seat belts—the white-knuckle thrills at Utopia, the world's most fantastic theme park, escalate to nightmare proportions in this intricately imagined techno-thriller by New York Times bestselling author Lincoln Child.

Rising out of the stony canyons of Nevada, Utopia is a world on the cutting edge of technology. A theme park attracting 65,000 visitors each day, its dazzling array of robots and futuristic holograms make it a worldwide sensation. But ominous mishaps are beginning to disrupt the once flawless technology. A friendly robot goes haywire, causing panic, and a popular roller coaster malfunctions, nearly killing a teenaged rider. Dr. Andrew Warne, the brilliant computer engineer who designed much of the park's robotics, is summoned from the East Coast to get things back on track.

On the day Warne arrives, however, Utopia is caught in the grip of something far more sinister. A group of ruthless criminals has infiltrated the park's computerized infrastructure, giving them complete access to all of Utopia's attractions and systems. Their communication begins with a simple and dire warning: If their demands are met, none of the 65,000 people in the park that day will ever know they were there; if not, chaos will descend, and every man, woman, and child will become a target. As one of the brains behind Utopia, Warne finds himself thrust into a role he never imagined—trying to save the lives of thousands of innocent people. And as the minutes tick away, Warne's struggle to outsmart his opponents grows ever more urgent, for his only daughter is among the unsuspecting crowds in the park.