United Airlines Flight 93 leaves Newark on the morning of September 11, 2001, roughly forty minutes behind schedule, a delay that puts it in the air just as the first two hijacked planes hit the World Trade Center. Four hijackers take the cockpit soon after takeoff, and the film reconstructs what happens next through cockpit voice recorder transcripts, air traffic control recordings, and interviews with the families of passengers and crew, along with government officials and terrorism analysts. Learning by phone that other hijacked planes have already been used as weapons, a group of passengers led by figures like Todd Beamer decide to storm the cockpit rather than wait to become the next one. The film lays out the evidence for the plane's suspected target, the U.S. Capitol or the White House, and follows the struggle that ends with the aircraft crashing into a field near Shanksville, Pennsylvania, killing all forty-four aboard. Kiefer Sutherland narrates. The account stays close to the timeline and the voices on the recordings rather than speculation.