Dagger of the Mind, TOS 1
A damned entertaining episode. A mind-altering technique (y’know, those spinning lights that go “brrrrwww” can be murder) pretty much stolen from Anthony Burgess is turning bureaucrats into violent intruders, plus Kirk is stuck on an away team with that pesky brunette he took home after the (no joke) biomedical Christmas party. A cop-out ending (Kirk overpowers the device just because he is cool, I guess) doesn’t ruin things too much; especially after the hardcore Kirk/McCoy protocol smack down & the first Vulcan mind-meld. But if someone could explain the Macbeth connection, I’d be appreciative.