A contest staged in 2269 by the rock-like Excalbians, who pitted Kirk and Spock with images of Lincoln and Surak against four notorious villains to study human ideas of good and evil.
The USS Enterprise was surveying the molten planet Excalbia when a figure of Abraham Lincoln appeared in space and asked to come aboard. Kirk and Spock accompanied him to a habitable patch on the surface, where an Excalbian named Yarnek explained the drama his people wished to watch.
In the Original Series episode The Savage Curtain the two officers are joined by Lincoln and by Surak, founder of Vulcan philosophy. Against them stand Genghis Khan, Colonel Green of Earth's 21st century, Zora of Tiburon and Kahless the Unforgettable. Yarnek threatens to destroy the ship if Kirk loses.
Surak and Lincoln are killed while seeking peace and rescue, but Kirk and Spock drive off the others. Yarnek remarks that the two sides used the same methods; Kirk answers that their aims differed.