In Ulster, Northern Ireland, a petty criminal kills a woman in a drunken car crash. Her sons swear revenge. In London, Sean Dillon and his colleagues in the “Prime Minister’s private army,” fresh from defeating a deadly al-Qaeda operation, receive a warning: You may think you have weakened us, but you have only made us stronger. In Washington, D.C., a special projects director with the CIA, frustrated at not getting permission from the President for his daring anti-terrorism plan, decides to put it in motion anyway. He knows he’s right --- the nation will thank him later.
On a dark summer night, two Chechen mercenaries emerge from the waters off Nantucket to kill a high-value target, the former president of the United States, Jake Cazalet. Unfortunately for them, Cazalet has guests with him, including black ops specialist Sean Dillon and his colleague, Afghan war hero Captain Sara Gideon. Dillon is curious as to how they even got on the island, and what he discovers sends a chill through his bones --- a name from very far back in Dillon’s past. If this man is working with the terrorists now, the assassination attempt is only the beginning --- and the next time, the results might be much, much different.
The President is coming to London, but not to a warm welcome --- a fanatical mullah is offering a blessing to anyone who will assassinate the President. A small band known as the "Prime Minister's private army" is called in, including intelligence captain and Afghan war hero Sara Gideon.