Over the Atlantic, an airliner's controls suddenly stop reacting. In Japan, an oil tanker runs aground when its navigational system fails. And in America, a nuclear power plant nearly becomes the next Chernobyl.

At first, these computer failures seem unrelated. But Jeff Aiken, a former government analyst who saw the mistakes made before 9/11, fears that there may be a more serious attack coming. And he soon realizes that there isn't much time if he hopes to stop an international disaster.

The West is under its greatest threat yet in Mark Russinovich's Trojan Horse. A revolutionary, invisible computer virus that alters data without leaving a trace--more sophisticated than any seen before--has been identified within the computers of the United Nations, roiling international politics. Cybersecurity analysts Jeff Aiken and Daryl Haugen are summoned to root it out and discover its source.

As the virus penetrates Western intelligence, and the terrifying truth about its creator is revealed, Jeff and Daryl find themselves in a desperate race to reverse it as the fate...