Episode Title: "MIRI"
Production Number: 12
Original Air Date: 10-27-66
Stardates: 2713.5, 2713.6, 2717.3
The U.S.S. Enterprise detects an old Earth-style S.O.S. signal from the third planet in a nearby Solar system -- a planet that is an exact duplicate of Earth. Captain Kirk leads a landing party to the planet, in a city where the signal originated. The landing party is attacked by a childlike, mutated humanoid, which quickly dies from an accelerated metabolism.
The landing party finds a girl named Miri and several other children who have been living on the duplicate-Earth for 300 years, since all the adults on the planet died after a life-prolongation vaccine was tested in the Twentieth Century. The children have prolonged lives, but when they reach puberty, they develop skin lesions and they mutate before going insane and dying. The members of the landing party, except Spock, quickly develop skin lesions, and they have only a few days to find a cure before they die from the disease, and the remaining children on the planet will eventually starve with no adults to provide food.
Spock and Dr. McCoy find a cure with equipment beamed down from the Enterprise, and after leaving a medical team on the planet with the children, Captain Kirk contacts Space Central to send teachers and advisers to take care of the children.
Factoid: Spock has green blood.
Dr. McCoy: "It's dead."
Guest Characters: Yeoman Janice Rand, Lt. Farrell
KEY: [brackets]=illusions *star=first appearance