From the New York Times bestselling author, a gripping pre-apocalyptic thriller about a first responder who must stop billionaire survivalists and their AI from turning the end of the world into a curated opportunity for absolute power

On the brink of global nuclear war, a social media post goes viral claiming a remote New Hampshire valley is a Shadow Zone, a unique place where people can take refuge from fallout and nuclear winter. Millions flood toward it, abandoning cities, laws, and morality in a desperate bid to survive.

Taken there against his will, New York City paramedic Michael Ryan discovers a fraught divide between hordes of newcomers seeking safety and occupants of a luxury doomsday bunker constructed on the site years before by a tech mogul. Protected by an all-seeing artificial intelligence and autonomous robotic weapons, the billionaire and his elite followers believe civilization deserves to collapse, and that they alone are fit to rule what comes after.

As the luxury bunker residents attempt to drive refugees from the valley's national forest and the countdown to nuclear annihilation continues, Ryan leads a ragtag team of hackers, engineers, and citizen soldiers on a quest to disrupt the billionaire’s post-apocalyptic plans and give ordinary people a chance to survive a crisis whose origins might not be an accident.