- Captain James T. Kirk: Captain's log, supplementary. We have buried the members of the Starnes exploration party. Everyone has been deeply affected by what has happened here - with some important exceptions.
- Mr. Spock: Evil does seek to maintain power by suppressing the truth.
- Dr. McCoy: Or by misleading the innocent.
- Captain James T. Kirk: Misleading the innocent? I wonder.
- Captain James T. Kirk: A child suppresses the fact that both parents are dead? I... I can't believe it.
- Mr. Spock: Humans do have an amazing capacity for believing what they choose, and excluding that which is painful.
- Captain James T. Kirk: Where is your friend? Where is that stowaway? Why does he hide?
- Mary: He will come, if we call him.
- Tommy Starnes: But we won't. We don't need him. We're not afraid of you!
- Dr. McCoy: As Medical Officer I must warn you that unless the normal grief is tapped and released from these children, you are treading dangerously.
- Mr. Spock: Captain, so long as the children are present, there is danger. They are the carriers.
- Captain James T. Kirk: Spock, they're not the alien beings, they're children being misled.
- Mr. Spock: They are followers. Without followers, evil cannot spread.
- Captain James T. Kirk: They're children!
- Mr. Spock: Captain, the 430 men and women on board the Enterprise, and the ship itself, are endangered by these... children.
- Captain James T. Kirk: They don't understand the evil that they're doing.
- Mr. Spock: Perhaps that is true. But the evil that is within them is spreading fast. And unless we can find a way to remove it...
- Captain James T. Kirk: ...we'll have to kill them.
- Mr. Spock: It appears we are no longer orbiting Triacus.
- Captain James T. Kirk: That's impossible. If we're not orbiting Triacus, then the men I beamed down... are dead.
- Captain James T. Kirk: I'm getting a feeling of anxiety in this place. It doesn't sound very scientific, does it? But it's strongest right here.
- Mr. Spock: I'm not aware of it, Captain.
- Captain James T. Kirk: Maybe that's what's registering on your tricorder.
- Mr. Spock: I am not familiar with anxiety, but I was not aware that it could be registered on sensors.
- Gorgan: I would ask you to join me; but you are gentle, and that is a grave weakness.
- Captain James T. Kirk: We're also very strong.
- Gorgan: Ah, but your strength is cancelled by your gentleness. You are full of goodness. Such as you cannot be changed. You are like the parents. You must be eliminated.
- Nurse Christine Chapel: [Nurse Chapel is getting the children ice cream sundaes] Would you like a surprise, Stevie?
- [He nods, takes a random card, but the food dispenser gives him his ice cream, his face falls]
- Steve: It's coconut and vanilla. They're both white!
- Nurse Christine Chapel: There, there now, Stevie. There are unpleasant surprises as well as pleasant ones. That was your unpleasant surprise. Now, what would you like for your *pleasant* surprise?
- Captain James T. Kirk: Whatever happened here... is locked up inside those children.
- Mr. Spock: The attack on Professor Starnes' party must surely have been unprovoked.
- Captain James T. Kirk: Attack? Mass suicide is what it seems to be.
- Mr. Spock: I stand corrected, Captain. 'Induced' would be a more precise term. Induced by an outside force.
- Captain James T. Kirk: Such as?
- Mr. Spock: The release of bacteria, or a helpless mental depression, and a state of suicidal anxiety could have been chemically induced.
- Professor Starnes: God forgive us. Must destroy ourselves! Alien upon us. The enemy from within. The enemy!
- Captain James T. Kirk: Did you see your father today?
- Tommy Starnes: [warily] I saw him.
- Captain James T. Kirk: Did he seem upset?
- Tommy Starnes: Yeah, he was very upset.
- Captain James T. Kirk: What about?
- Tommy Starnes: [resentfully] Well, I didn't ask him.
- Captain James T. Kirk: What was going on that would have upset him?
- Tommy Starnes: How should I know. He was always upset - just like you, Captain Kirk.
- Captain James T. Kirk: Aren't you unhappy about leaving Triacus?
- Tommy Starnes: THAT place? That's for adults.
- Captain James T. Kirk: Aren't you upset about... leaving your parents?
- Tommy Starnes: My parents? They love it down there - always busy. They're happy. Can I go now?
- Tommy Starnes, Mary, Steve, Don, Ray: [chanting] Hail hail, fire and snow. Call the angel, we will go. Far away, for to see, friendly Angel, come to me.
- Mr. Spock: According to the legend, Triacus was the seat of a band of marauders who made constant war throughout the system of Epsilon Indi. After many centuries, the destroyers were themselves destroyed by those they had preyed upon.
- Captain James T. Kirk: Is that the end of it?
- Mr. Spock: No. Like so many legends, this one, too, has a frightening ending. It warns that the evil is awaiting a catalyst to set it again into motion and send it marauding across the galaxy.
- Captain James T. Kirk: I think it's about time we found out whether Professor Starnes' enemy within... is on the planet below, or here on board ship with us.
- Gorgan: Friends, we have reached a moment of crisis. The enemy have discovered our operation. But they are too late. They no longer control the ship. We do. We shall prevail. They will take us any place we desire. So, back to your stations. Maintain your controls. If resistance mounts, call upon their beast. Their beast will serve us well. The fear in each one of them is the beast which will consume him. Remember how it was on Triacus. If they resist, so shall it be on the Enterprise.
- Captain James T. Kirk: Lieutenant. What're you staring at?
- Uhura: I see my death. A long... death. Disease, and pain. I see my death!
- Captain James T. Kirk: Mr. Sulu, I ordered you to change course. Mr. Sulu...
- Sulu: Captain, stay away form the controls! If you touch them, we'll be destroyed!
- Captain James T. Kirk: Scotty. I want you to override the bridge navigation system; plot a course for Starbase 4.
- Scott: I can't do that, sir.
- Captain James T. Kirk: Why not?
- Scott: [manipulated by Don] These are very sensitive instruments. I will not have you upset their delicate balance. We would all be lost, forever lost! - Go away now. Go away, or we'll kill ya.
- Gorgan: As you believe, so shall you do, so shall you do. As you believe, so shall you do, so shall you do.
- Gorgan: Who has summoned me?
- Captain James T. Kirk: I did, Gorgan. My... beast is gone. It lost its power in the light of reality. I command again. And I ordered you here.
- Dr. McCoy: [of the children] They're crying, Jim! I don't know how it happened, but it's good to see.
- Captain James T. Kirk: I'm losing command. I'm losing the Enterprise! The ship is sailing on and on. I'm alone! Alone... Alone... I'm losing command.
- Mr. Spock: Captain.
- Captain James T. Kirk: I've lost command. I've lost the Enterprise.
- Mr. Spock: Jim.
- Captain James T. Kirk: [calms down] I've got command. I've got command. I've got command.
- Mr. Spock: Correct, Captain.