In the days prior to and after the September 11, 2001 terrorist attacks, members of the FBI, CIA and various law enforcement communities struggle to ensure America's safety in a new government branch titled Homeland Security. Admiral Ted McKee is assigned to lead the new branch with help from his NSA liaison, Sol Binder, to prevent further terrorist attacks in America. McKee's teenage daughter Melissa is romantically involved with a teenage Arab immigrant named Yusef, whose father is detained by the authorities. But no one is aware that Yusef's father, Fazul, is not a terrorist spy... but Yusef is. Meanwhile, CIA agent Bradley Brand is sent to Afghanistan, with agent Johnson, to assist the Northern Alliance rebels in their fight against the Taliban and the Al Queada terrorist organization responsible for the 9/11 terrorist attacks in America, to find out more info on the 'Second Wave' of attacks. In Seattle, FBI agents Jane Fulbar and Frank Heinhoff try to link a Russian arms dealer to an AQ cell in the city planning to construct a 'dirty bomb' in preparation for the next AQ attacks, but find their work hampered by red tape.