Perry Mason is hired by a distressed girl who assumed the identity of a non-existent cousin to report her own disappearance as a suspected suicide.
Hyperaccelerated aliens, invisible to the naked eye, take over the Enterprise.
The sight of a Medusan ambassador causes insanity.
Kirk is confronted by one of his heroes, now criminally insane.
Kirk is forced into negotiating peace on a planet with severe class inequities.
