AllMovie

This episode of the 1960s science fiction series begins with the Enterprise coming across one of the most unexpected space travelers they have encountered: President Abraham Lincoln. Finding the long-dead President alive and well in outer space, a stunned Captain Kirk beams him aboard. The man, who indeed seems to be Lincoln, convinces Kirk and Mr. Spock to accompany him to the surface of a nearby planet. They agree, and Spock is similarly shocked when the trio is joined by Surak, a legendary Vulcan historical figure. The meaning of these strange encounters becomes clearer when the foursome meets a powerful alien, who explains that he is conducting an experiment to test the worthiness of their species, using them as examples. This test takes the form of a battle to the death with Kirk, Spock, Surak, and Lincoln on the side of good, against four historical representatives of evil, including Genghis Khan and the ruthless Klingon warrior Kahless. Kirk and Spock must band together with their idols to defeat their villainous opponents, or else they, and the Enterprise, shall be destroyed.