The Uninvited
"The Day of the Dove"
A luminous, swirling alien life form that thrives on hatred creates ill feelings among crewmen and also inspires a tension-filled conflict between Klingons and Enterprise officers. After the ship has changed hands several times, the opposing forces finally realize that an outside intelligence is governing their actions. United, Kirk and the Klingon Captain laugh the uninvited hate-mongering alien off the Enterprise.
