The untold story of how, in the desperate moments after the 9/11 attacks, the FBI must evacuate its New York headquarters - and transform its parking garage into the new command center. Resources are scarce. Disturbing questions quickly arise: What did we miss? Could we have prevented this? Within hours, though, agents launch the most complex - and important - criminal investigation in U.S. history. In the days that follow, they rewrite the rules for counter-terrorism operations forever.