Reviewing TOS- Where No Man Has Gone Before

Where No mas has gone before was the first indication to the fans of the nascent series that they could not always count on continuity "Wait, last week they had three colours of shirts- Scotty was in red, Spock was in Blue, Sulu was in yellow, but now..." Of course we know, from our perspective, that episodes were not broadcast in order of filming. WNMHGB has a some great moments, and a storyline not any more farfetched than other sci-fi- breaking the galactic barrier may turn some of your crew psychic, and some of those dangerously so. The most disappointing thing to me in this episode is Kelso's death; I thought he was a quite promising character! I also wonder what happened to the crewmen who were not Mitchell or Dehner, who were affected by crossing the galactic barrier. We know they exist; we heard Spock speak to Kirk of them. Do they eventually return to normal, or just stay somewhat enhanced forever?