September 11, 2001 unfolds through the actual radio traffic of the day: air traffic controllers in Boston puzzling over a plane that has stopped responding, cockpit transmissions from American 11 and United 175, and the military channels at NORAD trying to scramble fighters faster than the hijackers can act. The film reconstructs all four flights in sequence, from the first garbled warning signs to the strikes on the World Trade Center and the Pentagon and the crash of United 93 in a Pennsylvania field. History Hit assembles the timeline from recorded ATC communications, cockpit audio, and government transcripts rather than dramatization, letting the confusion and delay in the real exchanges carry the tension. Officials and controllers describe realizing, in real time, that the normal rules for handling a hijacking did not apply that morning. The result is less a retelling of the attacks than a record of how slowly and incompletely the information reached the people meant to stop them.