Spock, Messiah!

The victim of a cruel experiment, Commander Spock renounces the USS Enterprise, becomes the Messiah of the planet Kyros, and launches a holy war on the rest of the world. The USS Enterprise visits the planet Kyros to observe the population and test a new telepathic implant. The people living on the planet traditionally cover their faces, so the implant devices allow the crewmembers to mentally link with a member of the populace, accessing both their memories and instincts - which will allow the crew to walk around the planet freely. But something goes wrong when Ensign Sara George becomes sexually promiscuous. Following an away mission to the planet, Spock refuses to return to the ship and declares himself to be the messiah of the planet. He threatens to destroy some important crystals on the planet which are needed by the ship. Captain Kirk and the crew must retrieve Spock, obtain the critically-important crystals, and get the ship away before deadly radiation destroys them all.