Dagger of the Mind
Kirk and Dr. Helen Noel find the Federation's last colony for mental patients hiding dark secrets behind its caring facade, facing the "neural neutralizer".
Most one hour action/ adventure TV shows have an "asylum" episode, though in TOS it goes by penal colony, treatment facility, and other futuristic, proto-politically correct handles. The only original element is the neutralizer, a device promoting dangerous levels of over-acting. Kirk is naturally hit hardest, though somehow his love for the Enterprise prevents brainwashing. His erstwhile lover, Dr. Noel, isn't a very interesting character, going along with whatever Dr. Adams says or what Kirk tells her to do; she lacks willpower and creativity. Nor is the doctor a great villain, since he has no motivation and is simply assumed to be a sadistic maniac. The most interesting scenes occur aboard the ship, with Spock, McCoy, and the troubled Van Gelder. It's the first Vulcan mind meld! But it's not of much use, since Kirk and Noel acquire the same information on the surface. The theme of horrible loneliness and emptiness is firmly stated, but one can't help wishing that this episode weren't barren.
Spock Saves the Day: Spock nerve pinches Van Gelder, extracts vital information from him by mind meld, and beams down to shut off the planet's force field. (Ripping off a padlock with his bare hands!)
Oops: Spock's restarting the electricity fries Adams's brain. Oh well.
Developments: As stated the mind meld scene is by far the best here, and well played by Nimoy, ever expressive with his hands. Viewers will be equally hypnotized. It does seem protracted and quite verbally-oriented compared to later melds, but perhaps Spock wished McCoy to hear this stuff first-hand. A shame Kirk wasn't around to see, but he will soon.