Homeland is an American espionage thriller television series developed by Howard Gordon and Alex Gansa based on the Israeli series Prisoners of War. The series stars Claire Danes as Carrie Mathison, a CIA officer with bipolar disorder, and Damian Lewis as Nicholas Brody, a Marine Corps Scout Sniper. Brody was held captive by al-Qaeda as a prisoner of war, and Mathison becomes convinced that he was "turned" by the enemy and poses a threat to the United States. The series storyline grows from this premise, together with Mathison's ongoing covert work.