"The Cage", Star Trek: The Original Series' first pilot episode

"The Cage" is the original pilot episode of the original Star Trek science fiction series and resulting franchise.

It was completed in early 1965 (with a copyright date of 1964), but not broadcast on television in its complete form until 1988. The episode was written by Gene Roddenberry and directed by Robert Butler.

"The Cage" had most of the essential features of Star Trek, yet the differences between this episode and the series proper were manifold. The Captain of the starship USS Enterprise was not James T. Kirk, but Christopher Pike. Spock was present, but not as First Officer. That role was taken by a character known only as Number One, played by Majel Barrett. Spock's character differs somewhat from that seen in the rest of Star Trek: he displays a youthful eagerness that contrasted with the more reserved, logical Spock that is better known. He also gets the first line in all of Star Trek: "Check the circuit!"

NBC reportedly called the pilot "too cerebral", "too intellectual", and "too slow" with "not enough action". Rather than rejecting the series outright, however, the network commissioned — in an unusual and, at the time, unprecedented move — a second pilot: "Where No Man Has Gone Before".