The crew revives a group of genetically engineered tyrants led by Khan Noonien Singh.
The Enterprise comes upon the SS Botany Bay, a sleeper ship drifting for nearly two centuries, and Kirk, McCoy, Scotty and historian Marla McGivers find dozens of people in suspended animation. Their revived leader is identified as Khan Noonien Singh, a genetically engineered ruler who controlled over a third of Earth during the Eugenics Wars of the 1990s. Khan plays on McGivers's infatuation, wakes his followers and seizes the ship, threatening to suffocate Kirk in a decompression chamber unless the bridge crew yields.
McGivers relents and frees Kirk, who floods the ship with anesthetic gas and defeats Khan in hand-to-hand combat in engineering. Rather than send the group to a penal colony, Kirk exiles them to the untamed world Ceti Alpha V, and McGivers chooses to go with Khan. Written by Gene L. Coon and Carey Wilber, with Ricardo Montalban as Khan, the story continues in the 1982 film The Wrath of Khan.