After the 1908 Tunguska blast levels a Siberian forest the size of London, a Russian scientist makes an amazing discovery amongst the debris.

More than 60 years later, former Army combat engineer Tyler Locke rescues Fay from gunmen who are after a piece of wreckage she claims is from the Roswell incident. Incredulous of her tale, Tyler believes the attack on Fay is nothing more than a burglary gone wrong. But when he finds himself locked in the back of a truck carrying a hundred tons of explosives and heading for a top secret American base, Tyler knows that he has stumbled onto the opening gambit of something more sinister than he ever imagined.

Because disgraced Russian spy Vladimir Colchev is after an Air Force prototype code-named Killswitch, an electromagnetic pulse weapon of unprecedented power. Although Tyler is able to avert catastrophe at the US facility, Colchev gets away with the bomb and plans to turn it on America itself. To complete his mission, he needs only one other key component, a mysterious object recovered from the Roswell crash.

In a desperate race against time, Tyler must unmask a conspiracy a century in the making to rescue the United States from electronic Armageddon.