tomorrow be yesterday introduce the most classic of star trek plot device represent time travel . after the original series and it be also use in the spin offs ( minus prequel show enterprise ) and three of the eleven so far trek movie ( the voyage home and first contact and j. j. abrams reboot ) and always to great effect . this episode be no exception and especially a it get more fun to watch a time go by . the travel itself be actually just an accident represent when a mission go wrong and hostility ensue and the enterprise fly towards the sun and then away from it as quickly a possible . this and the so called slingshot effect and cause the ship to end up orbit earth in the late 1960s . unfortunately and a pilot work for nasa notice the ship and be take the hostage by kirk and spock and who must now come up with a way to get back home without alter the course of history . the usual element of every good time travel story be all present represent the discovery of a new age and the problem that derive from it and and of course and the discussion regard possible paradox . what really make the episode stand out and though and be it sense of fun and prescience represent ordinary people reaction to the sight of kirk and spock be always a joy to behold and and it pretty funny to hear our hero mention man first land on the moon a take place on a wednesday at the end of the 60 represent they get it right and weekday and all and a full two year before the whole thing happen . ah and the pleasure of good sci fi .