This is my vote for the all-time coolest episode ever--perhaps not the best, but definitely the coolest.
The landing party beams back on the ship, but through an impossible to believe coincidence, the exact same members from a parallel universe do the same thing at the same time and are switched! The nice Star Trek crew members now find themselves in an evil bizarro world where the ship and crew are ultra-militaristic and cruel. In this parallel world, decency is despised and people get ahead by killing their superior officers! So, Kirk being at the top of the evil pecking order is open to a series of attempts on his life. This is made worse by the fact that Kirk won't obliterate a peaceful planet when the Evil Federation orders him. So, the crew must keep who they really are a secret and find a way to return home.
Now, for the cool factor, the episode is chock full of it. Evil Spock looks and acts a lot like our good buddy Spock except he sports the neatest evil goatee AND he uses torture on poor old Evil Lt. Kyle when he thinks this crewman made a mistake (which he didn't!). Then, Evil Mr. Sulu is possibly even more cool because he sports a nifty scar on his face and is a homicidal maniac and sex pervert!! Then, Chekov tries to kill the Captain but when he fails he's placed in a horrible torture device! And, Kirk finds that in this world he not only has a sexy main squeeze but a secret device that makes his enemies vanish into thin air!!! The bottom line is that this episode is so much fun to watch. Instead of the usual prime directive and the overriding desire to do good, this anti-Enterprise world is just plain awful and a great counter-point to the sometimes saccharine-like world of Star Trek where everyone gets along a bit too often! It's a wonderful break from the usual and an episode you just can't miss.
The landing party beams back on the ship, but through an impossible to believe coincidence, the exact same members from a parallel universe do the same thing at the same time and are switched! The nice Star Trek crew members now find themselves in an evil bizarro world where the ship and crew are ultra-militaristic and cruel. In this parallel world, decency is despised and people get ahead by killing their superior officers! So, Kirk being at the top of the evil pecking order is open to a series of attempts on his life. This is made worse by the fact that Kirk won't obliterate a peaceful planet when the Evil Federation orders him. So, the crew must keep who they really are a secret and find a way to return home.
Now, for the cool factor, the episode is chock full of it. Evil Spock looks and acts a lot like our good buddy Spock except he sports the neatest evil goatee AND he uses torture on poor old Evil Lt. Kyle when he thinks this crewman made a mistake (which he didn't!). Then, Evil Mr. Sulu is possibly even more cool because he sports a nifty scar on his face and is a homicidal maniac and sex pervert!! Then, Chekov tries to kill the Captain but when he fails he's placed in a horrible torture device! And, Kirk finds that in this world he not only has a sexy main squeeze but a secret device that makes his enemies vanish into thin air!!! The bottom line is that this episode is so much fun to watch. Instead of the usual prime directive and the overriding desire to do good, this anti-Enterprise world is just plain awful and a great counter-point to the sometimes saccharine-like world of Star Trek where everyone gets along a bit too often! It's a wonderful break from the usual and an episode you just can't miss.