From London, Cairo and Washington, D.C. to Saudi Arabia, Switzerland and Nigeria, a team of American and British counter-terrorist agents attempts to track down a dangerous terrorist cell operating on a deadly global level. The nightmare begins after terrorists mistakenly release poisonous sarin nerve gas, killing themselves and guests at a London hotel. British MI5 and MI6 agents believe a local terrorist cell is targeting members of their counter-terrorism unit and plotting attacks on the London and New York City subways. But when the investigation broadens to include American agents from the FBI, CIA and NSA, the subway threat begins to feel like a diversion. As the agents rush to determine the terrorists' real plans, they find that they too have become targets in a deadly race to not only prevent the next attack, but to also disrupt the far-reaching terrorist network.