Spock's Brain First Airs
"Spock's Brain" is a third season episode of Star Trek: The Original Series, first broadcast September 20, 1968.
It was the first episode of the third season and the first to air after NBC moved the show from 8:30 P.M. to 10 P.M. on Friday nights. It was repeated July 8, 1969. It is episode #56, production #61, written by Gene L. Coon (under the pseudonym Lee Cronin) and directed by Marc Daniels.
Synopsis: On stardate 5431.4, the USS Enterprise, under the command of Captain James T. Kirk, encounters a curious ship of unusual design. Upon contact, the ship emits a transport beam and a mysterious woman appears to the Enterprise bridge. She stuns the entire crew using a bracelet-like device, then examines each of them, taking particular interest in Mr. Spock. She then somehow removes his brain and disappears. When the crew awakens, Dr. McCoy finds Spock lying on a bed in sickbay and discovers what has happened to him. Thankfully, owing to the unusual physiology of Vulcans, Spock's body can survive in this "brainless" state mechanically, giving Captain Kirk about 24 hours to find his stolen brain.