Synopsis by Hal Erickson
With Mission:Impossible regular Lynda Day George still on maternity leave, Marlyn Mason makes a guest appearance as IMF agent Sandy in "Crack-Up." For her first assignment with the team, Sandy plays a major role in a scheme to determine the identity of the Syndicate higher-up who hired professional hit man Peter Cordel (Alex Cord). Vital ingredients for the success of this mission include a rigged chess game and a special "black-out" drug. "Crack-Up" was scripted by Arthur Weiss from a story by Weiss, Robert Weiss and Phyllis White. The episode originally aired December 9, 1972, as the last Saturday-night Mission:Impossible offering before the series' move to CBS' Friday-evening lineup.