A strange alien substance causes the crew to ignore their inhibitions and act out their deepest desires, while the ship plummets out of orbit.
Spock commands a stranded away team when their shuttlecraft is marooned on a planet with hostile natives.
Stardate 5630.7:...or is there in beauty no truth? Miranda Jones, a telepath who studied mental disciplines on Vulcan, arrives with Ambassador Kollos, a Medusan - an alien life form whose physical form is so hideous, humanoid life forms are driven insane if they look upon him. Also beaming aboard is Larry Marvick, one of the original designers of the Enterprise - and hopelessly in love with Miranda, although she has chosen to spend her life serving as a liaison between the Medusans and other humanoids. Miranda senses that someone is actively contemplating murder, and suspects Spock is envious of her once-in-a-lifetime mission - but even Miranda is unaware of the real would-be killer and their target.moreless
Kirk, Spock, and McCoy land on a primitive planet to negotiate a mining treaty, but soon find themselves involved with intrigue and must flee with a pregnant woman into the surrounding mountains.
Kirk attempts to assist a primitive people that are ruled over by a computer named Vaal.