The first meeting with the Klingons ends with two empires being told to stand down by a people they thought helpless.
With war looming between the Federation and the Klingon Empire, Kirk and Spock visit the planet Organia, whose people appear to be primitive and peaceful. When the Klingons conquer the world, the crew tries to resist, but the Organians show no interest in the fight.
This is the first appearance of the Klingons, led by Commander Kor, played by John Colicos. The ending reveals surprising truths about the Organians and sets up the uneasy peace between the two powers that lasted through the series. It is celebrated for its twist.