While negotiations quickly break down between the Federation and the Klingon Empire, the Enterprise is sent to Organia, a planet of primitive people strategically located between the two sides. Kirk and Spock beam down in an attempt to convince the peaceful Organians to accept Federation aid and protection against the Klingons. When the Klingon forces attack the planet, the Enterprise and the Klingon forces square off to battle in orbit of the planet. Displeased by the outbreak of violence, the Organians reveal themselves to be powerful creatures of pure energy who easily neutralize the weapons on both ships, and force both sides to sign a peace treaty.

John Abbott (Ayelborne)
John Colicos (Captain Kor)
George Takei (Lt. Hikaru Sulu)
Nichelle Nichols (Lt. Uhura)
Peter Brocco (Claymare)
Victor Lundin (Klingon Lieutenant)
David Hillary Hughes (Trefayne)
Walt Davis (Klingon Soldier #1)
George Sawaya (Klingon Soldier #2)

• This episode introduces the Klingons, who appear as ruthless military dictators here.
  
• The Organians reveal that in the future, the Klingons and the Federation will be allies.
  
• Kor will return in the Deep Space Nine episodes "Blood Oath" and "The Sword of Kahless".
  
• The Organians will make another appearance in the Star Trek: Enterprise episode "Observer Effect".