While investigating the assassination of a rabbi in 1990, agents discover a Brooklyn-based terrorist cell with connections to Osama bin Laden. In 1993, cell members succeed in setting off a bomb in the World Trade Center, killing six people.

Clinton administration officials react to the rise in jihadi terror. Operations are planned targeting Osama bin Laden resulting in near misses. A profile of bin Laden emerges through interview footage with him and commentary from people who knew him.

A portrait of Khalid Sheikh Mohammed, the mastermind of the Sept. 11 attacks. A look at the men recruited to carry out the attacks, including their backgrounds and training. An examination of missed signals in Washington, D.C., prior to the attacks.