On the planet Jaris asks Scotty if he remembers anything about the murders. This occurs after Sybo was murdered. Scotty says he doesn't remember anything. But later on the ship, Scotty says he remembers Sybo's murder and relates what happens. Why didn't he say that he remembered the first time?
McCoy and Scotty put the dead Hengist in a chair - why? There's no way a recently dead body is going to stay propped up in one of those futuristic chairs.
Why does Kirk hold the hearing before they do the scan on Scotty's memories? They have the hearing and Kirk says they'll do it "later" - seems like it'd be a valuable piece of evidence to have during the hearing, and it doesn't seem to take very long.
The ID cards Kirk puts into the computer to verify their identity appear/disappear in close/long shots.
Kirk: The Argelians will be the first to panic. Let's get back to the briefing room. (leaves with Spock)
Sulu: (blissfully drugged) I wonder who it is we're not supposed to be afraid of. (spins in his chair as the rest of the bridge crew laugh)
Kirk: I know a place, where the women are so...
McCoy: I know the place!
Scotty: Let's go see!
Sulu: Captain...(injected with tranquilizer) ...whoever he is, he sure talks gloomy, hee hee.
Kirk: Man your post, Mr. Sulu. If any of the other systems go out, switch to manual override, and above all, don't be afraid.
Sulu: With an arm full of this stuff, I wouldn't be afraid of a supernova.
McCoy: When a man feels guilty about something--something too terrible to remember--he blots it out of his conscious memory.
Spock: In the strict scientific sense we all feed on death -- even vegetarians.
Spock: Women are more easily and more deeply terrified... generating more sheer horror than the male of the species.
Spock: Deriving sustenance from emotion is not unknown in the galaxy. And fear is among the strongest and most violent of the emotions.
This episode was written by Robert Bloch, perhaps best known as the author of the book Psycho, which was made into a movie by Alfred Hitchcock. Among other things, Bloch was also a short story writer; one of his best known short stories is Yours Truely, Jack the Ripper (which was later adapted for television for Boris Karloff's Thriller). This episode parallels that short story in many ways, especially in the aspect that Jack the Ripper is seen as being an immortal who is still alive and killing in the present.
Scotty makes a direct reference to the events in this episode during his appearance in The Next Generation episode, "Relics," saying he got into a "wee bit of trouble" the first time he visited Argelius.
Desilu No: 5149-36.