Carrie Mathison is a CIA operations officer who was recently reassigned to the agency's counter-terrorism center after conducting an unauthorized operation in Iraq.

While in Iraq, Carrie was warned that Al-Queda has managed to convince an American P.O.W. to join their cause. After learning about a recently rescued US Marine Sergeant who was missing in Iraq since 2003, Carrie suspects that the Marine is the threat she was warned about.

With the help of her old boss and mentor, Carrie now turns her efforts to investigating the recently-rescued Marine in hopes of preventing another terrorist attack on America.