Dr. McCoy: Jim, the analysis of this so far is potassium 35%, carbon 18%, phosphorus 1.0, calcium 1.5. Jim, the crew didn't leave. They're still here.
Captain James T. Kirk: What do you mean?
Dr. McCoy: These white crystals is what's left of the human body when you take the water away, which makes up 96% of our bodies. Without water, we're all just three or four pounds of chemicals.
Captain James T. Kirk: Among my people, we carry many such words as this from many lands, many worlds. Many are equally good and are as well respected, but wherever we have gone, no words have said this thing of importance in quite this way. Look at these three words written larger than the rest, with a special pride never written before, or since, tall words proudly saying, "We the People". That which you call Ee'd Plebnista, was not written for the chiefs of kings, or the warriors or the rich or the powerful, but for ALL the people! Down the centuries, you have slurred the meaning of the words, "We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty, to ourselves and our Posterity, do ordain and establish this Constitution". These words and the words that follow, were not written only for the Yangs, but for the Kohms as well! They must apply to everyone, or they mean nothing!
Cloud William: Ay plegli ianectu flaggen, tupep like for stahn...
Captain James T. Kirk: And to the Republic for which it stands, one Nation, under God, indivisible, with Liberty and Justice for all.
Dr. McCoy: Spock, I've found that evil usually triumphs - unless good is very, very careful.
Cloud William: That which is ours is ours again. It will never be taken from us again.
Dr. McCoy: Spock, we gotta do something.
Mr. Spock: I'm open to suggestions, Doctor.
Dr. McCoy: [notices Spock concentrating on Sirah] What're you doing?
Mr. Spock: I'm making a suggestion.
Dr. McCoy: Who knows? It might eventually cure the common cold, but lengthen lives? Poppycock! I can do more for you if you just eat right and exercise regularly.
Captain Tracey: They sacrificed hundreds, just to draw us out in the open. And then they came, and they came. We drained four of our phasers, and they still came. We killed thousands and they still came.
Captain James T. Kirk: If my ancestors were forced out of the cities... into the deserts, the hills...
Mr. Spock: Yes. I see, Captain. They would've learned to wear skins, adopted stoic mannerisms, learned the bow and the lance.
Captain James T. Kirk: Living like the Indians, and finally even looking like the American Indian. American... Yangs - Yanks? Spock - Yankees!
Mr. Spock: Kohms... Communists? The parallel is almost too close, Captain.
Captain James T. Kirk: But if it were true, all these generations of Yangs were fighting to regain their land...
Sirah: You're a romantic, Jim.
Captain James T. Kirk: Does not your... sacred book promise that good is stronger than evil?
Sirah: Yes, it is written. Good shall always destroy evil.
Mr. Spock: Does our involvement here also constitute a violation of the Prime Directive?
Captain James T. Kirk: We merely showed them the... meaning of what they were fighting for. Liberty and freedom have to be more than just words. Gentlemen, the fighting is over here. I suggest we leave them to discover their history - and their liberty.
Dr. Carter: [from the ship surgeon's last log entry] If... if you've come aboard this ship... you're dead men! Don't go back to your own ship. You have one chance: get down there, get down there fast! Captain Tracey... is...
[screams and collapses]
Captain James T. Kirk: [to Spock] Keep working on the window if we're ever gonna regain our freedom.
Cloud William: Freedom?
[he gets up]
Cloud William: Freedom?
Captain James T. Kirk: Spock.
Mr. Spock: Yes, I heard, Captain.
Cloud William: That is a worship word, Yang worship. You will not speak it.
Captain Tracey: Outside. Or I'll burn down both your friends now.
Captain James T. Kirk: Why did you not speak until now?
Cloud William: You speak to Kohms. They're only for killing.
[Spock has rendered the Yang woman unconscious by a nerve pinch]
Captain James T. Kirk: Pity you can't teach me that.
Mr. Spock: I have tried, Captain.
Captain James T. Kirk: In my land we have a tribe like you.
Cloud William: Where is your tribe?
Captain James T. Kirk: Up there. One of those points of light that you see at night.
Yang Scholar: Why are you here? Were you cast out?
Captain James T. Kirk: You're confusing the stars with heaven.
Captain Tracey: He was cast out! Don't you recognize the Evil One? Who else would trick you with your own sacred words? Let your God strike me dead if I lie. But he won't, because I speak for him.
Mr. Spock: My need for attention is vital, Doctor, but our need for departure is even more immediate.
Mr. Spock: Lieutenant Galloway and I are checking out the lower levels. There seems to be no one on board. Only uniforms.
Mr. Spock: Captain Tracey is being quite factual in several statements. One - The Yangs are totally contemptuous of death. They seem incredibly vicious. Two - He is also being factual in that the Yangs are massing for an attack. There are signs of thousands of them in the foothills beyond. However, he was less than truthful in one very important matter.
Captain James T. Kirk: [recognizing what Spock hands him] Phaser power packs.
Mr. Spock: Captain Tracey's reserve belt packs - empty. Found among the remains of several hundred Yang bodies.
Captain Tracey: [excitedly] You've isolated the serum?
Captain James T. Kirk: [shouting] There's no serum! There're no miracles! There's no immortality here! All this is for nothing!
Captain Tracey: Explain it to him, Doctor!
Dr. McCoy: Leave medicine to medical men, Captain! You found no fountain of youth here!
Captain James T. Kirk: Although it appears the infection may strand us here the rest of our lives, I face an even more difficult problem - a growing belief that Captain Tracey has been interfering with the evolution of life on this planet. It seems impossible. A star captain's most solemn oath is that he will give his life, even his entire crew, rather than violate the Prime Directive.
Captain Tracey: How long would a man live if all disease were erased, Jim?
Captain Tracey: This immunizing agent here, once we've found it, is a fountain of youth. Virtual immortality, or as much as any man will ever want.
Captain James T. Kirk: For sale by...?
Captain Tracey: [... ] By those who own the serum. McCoy will eventually isolate it. Meanwhile, you inform your ship your situation's impossible. Order them away. When we're ready, we'll bargain for a whole fleet of ships to pick us up. And they'll do it.
Captain James T. Kirk: Yes, I suppose they would.
Captain Tracey: We've got to stay alive. Let the Yangs kill us and destroy what we have to offer, and we'll have committed a crime against all humanity. I'd say that's slightly more important than the Prime Directive. Wouldn't you, Jim?
Captain Tracey: [about the Yangs] Animals, who happen to look like us. Still think the Prime Directive's for this planet?
Captain James T. Kirk: I don't think we've a right or the wisdom to interfere, however a planet is evolving.