Episode Title: "THE IMMUNITY SYNDROME"
Production Number: 48
Original Air Date: 01-19-68
Stardates: 4307.1, 4309.2
The U.S.S. Enterprise is approaching Starbase 6 for a period of rest and recreation, when Spock senses that the starship Intrepid -- manned by 400 Vulcans -- has been destroyed, and Starfleet orders the Enterprise to investigate in Sector 3-9-J, where all contact has been lost with system Gamma Seven-A, which the Intrepid was investigating.
The Enterprise finds a black void drawing energy from the surrounding region; after the ship is drawn into the void, the crew finds a huge single-celled organism at the center. Commander Spock takes a shuttle into the organism and learns that it is preparing to reproduce.
Captain Kirk takes the Enterprise into the organism and launches an antimatter probe into its nucleus to destroy it before the organism can duplicate itself.
Factoid: Gamma Seven-A was a fourth-magnitude sun with billions of inhabitants in its system.
Factoid: The Coal Sack is a Galactic nebula.
Factoid: Vulcan has not been conquered within its collective memory. Memory goes back so far that no Vulcan can conceive of a conqueror.
Guest Characters: Nurse Christine Chapel, Lt. Kyle, Lt. Leslie
KEY: [brackets]=illusions *star=first appearance