Since the death of Osama bin Laden, Yemen has become the hottest front in the war against Al Qaeda. Now, with headlines about a terrorist plot to bomb a U.S.-bound airliner, award-winning reporter and FRONTLINE correspondent Ghaith Abdul-Ahad travels into the heart of Yemen's radical heartland. His first hand report shows how members of Al Qaeda in the Arabian Peninsula (AQAP) have taken advantage of turmoil in the country to impose their rule on areas of south Yemen. As the US expands its drone war to prevent terrorists from establishing a new safe haven, FRONTLINE shows how AQAP is taking control of towns and cities in an attempt to establish its own state. Also in this hour, the story of Al Qaeda operative Fahd al Quso --killed in a U.S. drone strike in Yemen early this month - as told by former FBI agent Ali Soufan who first interrogated him before 9/11.