There is an episode in the final season where they were fooled into believing they had landed on one of the planets of AC by a bunch of aliens disguised as young 60's earth hippies. That episode was called, "The Promised Planet."
Source of the confusion may be that the described finale was from the second series. The original series I think just got cancelled, no big finish.
Original series, The Promised Planet:
https://www.imdb.com/title/tt0636237/?ref_=ttep_ep19
Netflix reboot, Trust
https://www.imdb.com/title/tt13675378/?ref_=ttep_ep8