Data Stellare sconosciuta: L'Enterprise scopre attorno a Omega IV la Exeter, il cui equipaggio è ridotto in cristalli a causa di un virus. Ormai contagiati, Kirk, Spock e McCoy scendono sul pianeta per cercare una soluzione. Qui trovano il Capitano della Exeter che, in violazione alla Prima Direttiva, ha utilizzato i phaser contro la popolazione indigena.

McCoy: Without water, we're all just three or four pounds of chemicals. [T:05:16]

Kirk: A star Captain's most solemn oath is that he will give his life, even his entire crew, rather than violate the Prime Directive. [T:09:28]

McCoy: ...bacteriological warfare ...hard to believe we were once foolish enough to play around with that. [T:10:24]

Kirk: I don't think we have the right or the wisdom to interfere, however a planet is evolving. [T:17:55]

Kirk: Does not your sacred book promise that good is stronger than evil?
Sirah: Yes, it is written. Good shall always destroy evil. [T:40:01]

McCoy: Spock, I've found that evil usually triumphs, unless good is very, very careful. [T:40:38]

Kirk: This was not written for chiefs. Hear me. Hear this. Among my people we carry many such words as this from many lands, many wolds. 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 all the rest with a special pride never written before or since. Tall words, proudly saying «We the people...» That which you call «E Plebnista» was not written for the chiefs or 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 tranquillity, provide for the common defense, promote the general welfare and secure the blessing of liberty to ourselves and our posterity do ordain and establish this Constitution...». These words and the words that follow werw not written only for the Yangs, but for the Kohms as well...
Cloud William: For the Kohms?
Kirk: They must apply to everyone or they mean nothing! Do you understand? [T:44:31]

Kirk: We merely showed them the meaning of what they were fighting for. Liberty and freedom have to be more than just words. [T:46:29]