The morning of Sept. 5, 1972, began like any other for producer Geoffrey Mason and his ABC Sports team in Munich: another day of capturing the “thrill of victory and the agony of defeat” at the Summer Olympic Games. But as dawn broke, the control room received word that something was terribly wrong.

Details emerged. Members of the Palestinian militant group Black September had taken 11 Israeli athletes hostage, demanding the release of hundreds of prisoners held in their country’s jails. Inside the cramped ABC control room, instead of covering athletic triumphs, members of the ABC Sports team suddenly found themselves reporting on a life-or-death crisis playing out in real time a few hundred meters away, as the world watched in horror.

“At one point, the doors of the control room busted open and the German police came in, armed with machine guns, and told us to turn the camera off,” Mason, now 84 and the only surviving member of the core ABC team, recalled on a recent afternoon over Zoom from his home in Naples, Fla. “That was a seminal moment because we realized what we were doing was having real impact.” Hours later, the situation reached a tragic climax when a failed rescue attempt at a nearby airfield led to the deaths of all the hostages , along with five of the attackers and a West German police officer.

Now, more than 50 years later, the gripping period thriller “September 5” (in theaters Nov. 27) brings these tense moments — the first time a terror.