Kirk beams down to the planet Gideon and appears to find himself trapped on a deserted Enterprise. Spock on the real Enterprise must use his diplomatic skills to deal with the uncooperative inhabitants of Gideon and find the Captain.
After the Enterprise landing party beams down to investigate a geologically interesting planet, their ship is hurled across the galaxy. Kirk and company find a deserted outpost guarded by the deadly image of a beautiful woman.
Kirk, Spock, Abraham Lincoln, and Surak are pitted in battle against four notorious villains from history for the purpose of helping a molten rock creature's understanding of a concept he does not understand, 'good versus evil'.