AllMovie

The Enterprise's quest to cure a deadly illness brings them into an encounter with a mysterious man who may not be what he appears in this episode of the 1960s science fiction series. The search for a cure for the illness, which has infected the crew of the Enterprise, leads the starship to seek out an isolated world that serves as home to a reclusive genius known as Flint. Captain Kirk, Mr. Spock, and Dr. McCoy visit the world in an attempt to acquire the cure. Negotiations sour, however, when Rayna, a female android who serves as Flint's "companion," falls in love with Kirk. This fact arouses anger and jealousy in Flint, who withholds the cure as a result. Matters become even more complicated when Spock discovers a shocking secret about the recluse's past, one which casts a whole new light on the nature of his wisdom.