Suppose that you found the Fountain of Youth, and thought that you could live hundreds of years, if only you could learn its secrets. Well, Captain Tracey of the starship Exeter believes he has found this "Fountain of Youth" on the planet where he is now stranded. The remainder of his small crew complement is dead, and Tracey has sent a distress call which the USS Enterprise has intercepted. The Enterprise establishes an orbit around the planet and Kirk and Spock transport down, where they are greeted by Captain Tracey. The Captain is unharmed, and living among a humanoid species, the Kohms, who resemble Earth Asians, and are clad in animal skins to protect themselves against the harsh and frigid climate. But Wait!! Did Tracey send the distress call in order to be rescued, or does he really want something else? His unsettling manner, and the story he relates, leave some doubt.
When the Exeter established orbit around this planet years before, and made "first contact", Tracey and his crew encountered two humanoid species, who were participating in an ongoing brutal conflict. The first race, the Kohms, are a seemingly gentle and contemplative species, and not aggressive, despite the nature of their current conflict. The second race, the Yangs, resemble Northern European Caucasians. The Yangs also dress in animal skins, both males and females, but unlike the peaceful Kohms, they are warlike and brutal, at least according to Tracey's description of them. These two peoples have been trying to exterminate each other for quite a long time. So why would Tracey remain on this planet, at the cost of his crews' lives, when he had not been assigned to do so? The Federation Prime Directive expressly forbids the interference of Starfleet personnel in the affairs of any developing alien culture. As a direct result of Tracey's decision to remain, his crew perished in the conflict, one by one, until only Tracey remained, obstinately persisting in his obsession to discover the secret of the Kohms' longevity. He had discovered that the Kohms' lifespans extended to several hundreds of years. Tracey had summoned the Enterprise, not because of actual distress, but to access the Enterprise's firepower, in order to resolve the conflict between the planet's two races in favor of the Kohms, thus enabling Tracey to locate the source of the Kohms' secret. Tracey believes that the importance of such a discovery far outweighs the violation of the Prime Directive.
Kirk senses immediately that Tracey has lost touch with the fundamental purpose of the Federation, which is exploration and discovery, but always with the governing principle of non-interference. Kirk recognizes Tracey's violation and demands that Tracey accompany Spock and himself back to the Enterprise. But as they are debating, LOOK OUT!! The Yangs are attacking the Kohm village and capturing Tracey, Kirk, and Spock. This capture and imprisonment seem to validate Tracey's contention that the Yangs are, in fact, barbarians.
Now Tracey, Kirk and Spock are bound by ropes and held under guard inside a large tent, which serves as a gathering hall for the Yangs. The leader of the Yangs is a man named Cloud William. He is a tall, rugged man with short blond hair. His mate is a primitive looking woman with long, black hair, dressed in an animal skin. The other Yangs are surrounding the prisoners. Some are standing by Cloud William. One of the Yangs is an old man who serves as an advisor to Cloud William. Kirk and Spock, upon overhearing the Yangs' discussions, begin to realize that these Yangs are not as primitive as Tracey made them out to be. However they do express themselves in a simple and superstitious manner. Their culture appears to be in its infant stage. Cloud William speaks slowly and deliberately, but always speaks to the point. Kirk is trying to comprehend Cloud William's unusual manner of speaking and the symbolic elements of his culture, at least those that Kirk can see or hear from his confined position, under guard. Kirk is trying to find a "common ground" so that he has a starting point from which to try to reason with the Yangs.
Unfortunately, the Yang language is cluttered with words and references that Kirk simply does not understand. Cloud William continues to refer to some sort of fundamental doctrine, something called the "E Plebnista" which guides the Yangs' decisions regarding the dispensation of justice, and how they should deal with outside threats to their culture. Cloud William's advisor is explaining to him that there is no proscribed method to determine whether Kirk or Tracey represent a threat to the Yangs, and which of their conflicting stories is true, and which false. In response to William's interrogation, Kirk has described his and Spock's presence, and motives, truthfully (within the couched terms necessitated by the Prime Directive). Tracey, on the other hand, has presented a different version (completely untrue and self-serving, of course). William determines that the only just resolution is to kill all three. During the Yangs' heated deliberations, Kirk notices a book, prominently displayed, which Kirk theorizes might contain the tribe's "basic doctrine." Suddenly, from the recesses of the tent, one of the Yangs emerges holding a United States flag with fifty stars on a field of blue and the traditional red and white stripes. Though tattered and ragged, it is unmistakeably the Stars and Stripes. What the Hell??!! Kirk and Spock whisper to each other. How is this possible? This planet is light years from Earth. And they had never been exposed to earth culture prior to Tracey's arrival on the Exeter. So how could they possibly possess an American flag and what appears to be a Christian bible? Spock suggests to Kirk that this could be an example of Hodgkins' Theory of Parrallel Planets. Hodgkins' theory proposed that common cultures and symbols could arise on different planets in the galaxy,even though far-removed from each other, and having had no contact. Hodgkins said this was due to the nature of duality.
Kirk interpolates Spock's suggestion with Cloud William's confusing references and American earth culture. William's mate and others are frightened. Just as Kirk is talking reasonably to William, the fighting outside th tent has ceased, th Yangs have defeated the Kohms. Suddenly it dawns on Kirk. Earth. of course. Yangs means Yankees, or Americans. Spock thn suggests that Kohms my stand for Communists. Tracey has given up his attempt to convince Kirk or the savages, but rather thn helping Kirk, he decides to ty to drag him to death wth him. Kirk shouts "Wait" to Cloud William. "Does not your "book" say that Good triumphs over evil?" The councillor confirms this. "Let us fight" says Kirk. "Tfracey and I. Surely good will prevail." Cloud Willim consents, and the Yangs fom a circle around the two. Spock says "Captain, I've discovered tht Evil usually wins, unless good is very very clever."
It is a tough fight, and very vicious, but Kirk is the winner. Cloud William humbles himself before Kirk, and says "I doubted you because you did not know the words of the E Plebnista." Kirk says "I did not know them because you said them so badly." Thn kirk picks up the "holy" scroll that William had been handling the entire time and begins to read it aloud. "Not E Plebnista!!" says Kirk. "Listen." Then he reads the words.
" We the people in order to form a more perfect union, establish justice, ensure domestic tranquility, priovide for the common defense, promote the general welfare and, insure the blessings of liberty, to each man and his posterity, do ordain and establish this Constitution of the United States of America. Tracey i arrested and tkn bak to the ship. The Yangs have defeated the Kohms, and Kirk and Spock are released. Wow. All is resolved.