The Enterprise traces a virus-like outbreak that seems to be traveling in a direct line across a planetary system. The next planet is home to Kirk's brother Sam, his sister-in-law and their young son. The Enterprise arrives too late however for Sam. They find flying jellyfish-like creatures that attach themselves to humans. They take over the victims nervous system forcing them to bend to their will. Spock finds a weapon to use against the creatures but it leaves him hopelessly blind.
Did You Know?
This is one of only three original series episodes in which the word "damn" is used, with McCoy cursing the "damnable logic" behind the experiments designed to destroy the blastoneurons. The only other uses of the word "damn" occur in Star Trek: The Original Series: Journey to Babel
(1967), wherein Kirk admits he can't "damn" Spock for his loyalty by taking command of the Enterprise at the cost of Sarek's life, and in Star Trek: The Original Series: Court Martial
(1967) where Kirk makes a log entry stating that the evidence against him is "damning." During the 1960s, "damn" and "hell" were usually considered unacceptable on television (although hell might be allowed for naming a theological locale, as in several The Twilight Zone
(1959) occasions). This remained the case until All in the Family
(1971) came along in 1971. See more
Before the Enterprise leaves orbit, there is a close-up of the helm and navigation consoles; a crewman in a red tunic can be seen at the helm. Previous and subsequent shots show Sulu at the helm in his standard gold tunic. See more
I am a Vulcan, doctor. Pain is a thing of the mind. The mind can be controlled.
You're only half Vulcan. What about the human half?
It is proving to be an inconvenience, but it is managable.
Special Enhanced version Digitally Remastered with new exterior shots and remade opening theme song See more
References The Brain Eaters
Music credited to Alexander Courage
, although it strongly resembles the main title music for 'Hollow Triumph (1948)' by Sol Kaplan
Sung by Loulie Jean Norman See more