Space Seed

TOS Season 1 Episode 22
Air Date: February 16th, 1967

Finally, Khaaaaaaannnnn!. Oh wait, too soon.

Space Seed is the episode that introduces the character Khan. Khan, a product of the eugenics war, the third and final world war. Khan was one of a group of supermen genetically engineered. Due to his superiority he felt the world should be ruled by him. He was known as a fair dictator and there is a scene where Kirk and McCoy were joking with Spock over admiring Khan.

The Enterprise finds Khan's ship, The Botany Bay, where Khan and his people are in cryostasis. Khan ends up charming a federation historian, Lieutenant Marla McGivers, using her loyalty to him to take over the Enterprise. Khan then threatens to kill Kirk unless the crew of the Enterprise joins him. This causes McGivers to betray Khan (a double betrayal) since she doesn't want Kirk to die. Once Kirk beats Khan (in another battle in engineering with an obvious stunt double), Kirk decides to free Khan and strand him and his people on a planet where they could build a life for themselves. McGivers joins Khan.

The writing of the episode itself was kind of weak. Kirk gives Khan access to the ships technical specifications as reading material, which seems like a security risk. It also felt it weird that Khan could take over the Enterprise and McGivers committed mutiny but then be given full pardons at the end.  Ricardo Montalbán who plays Khan does give a great performance. I kind of wish we would have seen more of him before Star Trek II.