The 77th episode of Gene Roddenberry’s science fiction series Star Trek airs on NBC. Lee Bergere and Barry Atwater guest star. This episode features the last Klingon seen in the original television series. 
Stardate 5906.4: Over the planet Excalbia, the Enterprise is intercepted by who appears to be Abraham Lincoln, floating through space. Beaming aboard, Lincoln is welcomed by Kirk, who is somewhat awed by the presence of one of his most revered figures of history. “Lincoln” extends an invitation to Kirk and Spock to visit the planet, whose normally lava-covered surface sprouts a zone of Earthlike safety just for the landing party. Kirk, Spock and Lincoln are joined on the surface by an image of Surak, who initiated the doctrine of emotional restraint on Vulcan. A rock-creature appears and introduces Kirk and Spock to four more illusionary figures from history, this time the fiercest conquerors, tyrants and villains of the past, from Earth’s Genghis Khan to Kahless the Unforgettable, who, as Surak did for Vulcan, set the standard of behavior for the Klingons. The creature pits the best and most noble – Kirk, Spock, Lincoln and Surak – against the most vile historical figures. The rewards for Kirk and Spock, should they survive, are their lives, and the lives of everyone aboard the Enterprise.
teleplay by Gene Roddenberry and Arthur Heinemann
story by Gene Roddenberry
directed by Herschel Daugherty
music by Fred SteinerCast: William Shatner (Captain James T. Kirk), Leonard Nimoy (Mr. Spock), DeForest Kelley (Dr. Leonard McCoy), James Doohan (Mr. Scott), George Takei (Lt. Sulu), Nichelle Nichols (Lt. Uhura), Walter Koenig (Chekov), Lee Bergere (Abraham Lincoln), Barry Atwater (Surak), Phillip Pine (Colonel Green), Arell Blanton (Chief Security Guard), Carol Daniels DeMent (Zora), Robert Herron (Kahless), Nathan Jung (Genghis Khan)
Notes: Colonel Green was seen again in one of the final installments of Star Trek: Enterprise, depicted as a xenophobic warmonger whose rants inspired John Paxton’s attempt to oust all alien influences and visitors from Earth a century before Kirk’s tour of duty on the Enterprise. Kahless will reappear under very different circumstances during The Next Generation, and Surak will also resurface in a story arc on Enterprise.
LogBook entry by Earl Green