CIA agent John Wells has been undercover so long that his bosses are no longer sure he's still loyal - or even still alive.For years Wells has been building his cover in the mountains of Afghanistan, his existence known only to a few senior CIA officials. But now he's coming home - and no one, including his CIA minder Jennifer Exley, knows what to expect.He is a man alone, used by two adversaries and trusted by neither. And as terrorists prepare to unleash the most devastating attack in history,...