We all remember that fateful day, but few of us know what really happened when Flight 77 slammed into the Pentagon, forcing ordinary men and women into the most extraordinary circumstances of their lives.

Through eyewitness accounts, track the 757 as it descended to within 3,000 feet of the White House, banked over the Potomac River, made a sharp turn and headed straight for the Pentagon, knocking down lamp poles and street signs as it flew. Nearly 200 people lost their lives that day, and hundreds more were injured. Yet amidst the shock and sorrow, the triumph of the human spirit shone through. Hear from a worker in the Army's Accounting Office, whose unplanned meeting on another floor took her away from her normal workspace – and saved her life. Meet Lt. Col. Marilyn Wills, who wrung precious drops of water from her sweater – drenched by the building's sprinklers – into the mouths of gasping victims as she crawled from the rubble. And follow the men and women of the Fairfax County Urban Search & Rescue team, who – when reports came in that a second aircraft was headed for the Pentagon – were torn between saving their own lives and continuing their search efforts. From the testimonies of survivors, rescuers and those who lost loved ones, discover the untold stories of heroism – and tragedy – behind the attack on the Pentagon.