It's a routine takeoff on an ordinary morning in 2015 when Germanwings Flight 9525 leaves Barcelona for Dusseldorf. But something goes horribly wrong over the French Alps. The plane begins rapidly descending and air traffic control gets no response from the cockpit. Everyone's worst fears are realized when the plane is found smashed to pieces in the mountains. All passengers and crew aboard are dead. As the investigation unfolds, grief soon turns to horror when black box data points to a possibility so dark, it's almost beyond belief.