The Gary Seven one. The final second season episode.
As a child this was always one of my favourites. I liked the idea of these future guys coming back and visiting our time, and Trek went on to use the idea many times again -- ST:IV The Voyage Home, 'Past Tense' TNG, and 'Future's End' VOY among them.
'Tomorrow is Yesterday' established that the USS Enterprise could go forward and back in time, but because they had already bought a variety of other story ideas which were not dependent on Time Travel, it was never used until now.
'Assignment: Earth' was written as a half-hour series pilot while 'Star Trek's' first season was still in production. One of a select group of humans, trained by aliens to help Earth survive a difficult time period in history, Gary Seven operates out of Apartment 12B, 811 East 68th Street. I think Gary Seven's exploits, with his assistant Roberta Hornblower, against the shape changing Omegan agents, would have been a great series, but it did not sell. The script was rewritten into the Trek format and became a ST episode instead.
As a child this was always one of my favourites. I liked the idea of these future guys coming back and visiting our time, and Trek went on to use the idea many times again -- ST:IV The Voyage Home, 'Past Tense' TNG, and 'Future's End' VOY among them.
'Tomorrow is Yesterday' established that the USS Enterprise could go forward and back in time, but because they had already bought a variety of other story ideas which were not dependent on Time Travel, it was never used until now.
'Assignment: Earth' was written as a half-hour series pilot while 'Star Trek's' first season was still in production. One of a select group of humans, trained by aliens to help Earth survive a difficult time period in history, Gary Seven operates out of Apartment 12B, 811 East 68th Street. I think Gary Seven's exploits, with his assistant Roberta Hornblower, against the shape changing Omegan agents, would have been a great series, but it did not sell. The script was rewritten into the Trek format and became a ST episode instead.