On September 11, 2001, one hijacked plane never reached its target when United 93 crashed in rural Pennsylvania. Previously classified streams of evidence are combined to piece together what really happened in a gripping minute-by-minute account. Evidence includes secret service documents, air traffic control transmissions, phone records, voicemails, first person testimony and a top-secret audio recording that helps reveal details of Flight 93's crucial final moments. It's a story of heroism in the face of tragedy and sheds light on some of the biggest mysteries of that fateful flight.