Synopsis by Hal Erickson
European business tycoon Carl Vandaam (Alf Kjellin) hopes to recoup his lost fortune by building a hydrogen bomb and selling it to the highest bidder. The IMF's mission is to stop Vandaam in his tracks, a strategy that requires Rollin to pose as one of the potential buyers. The more dangerous aspect of the mission is to remove the plutonium from the completed bomb without blowing up everyone and everything in sight. "Doomsday" was written by Laurence Heath; the episode made its network broadcast debut on February 16, 1969.