"Nightfall" is the code name of a widespread terrorist attack planned by a secret organization called the Pendulum. The IMF must learn the nature of the attack, and also bring down Pendulum leader Gunnar Malstrom (Dean Stockwell). As an interesting change of pace, the viewer is given far more plot information than the IMF in the course of the story. Written by Calvin Clements Jr. and originally telecast on February 22, 1973, "The Pendulum" was the last Mission:Impossible episode to be filmed, though not the last to be aired. ~ Hal Erickson, All Movie Guide