Spock comes down with a case of Pon Farr, a kind of Vulcan estrus. Vulcans, we learn, need to mate every seven years. If they don't they'll die.
Kirk redirects the Enterprise to the Vulcan homeworld so that Spock can marry his betrothed, the beautiful T'Pring. But T'Pring, who has other plans, manipulates the situation into a fight to the death between Spock and Kirk.
Penned by science fiction author Theodore Sturgeon, "Amok Time" contains the the first use of the famous Vulcan benediction, "Live long and prosper." The episode also has the first use of the Vulcan hand symbol, which Leonard Nimoy based on a Jewish blessing.
