This is a typically sub-average episode of the 3rd season and since the 3rd season was not very good compared to the 1st and 2nd seasons, well, you can see where this is going. There appears to be some mystery, action, tension and sf adventure thrown into the mix here but none of it adds up to much by the end. The Enterprise arrives at a planet which even Spock can't explain: it's about the size of our moon but has Earth's characteristics. There's mention, also, that it's only several thousand years old and anyone with minimal knowledge of astronomical/geological time measures knows this is not possible for a natural planet. Kirk beams down with McCoy, Sulu and a geologist (uh-oh, expendable red-shirt alert) and the ship is immediately transported nearly 1000 light years away. Huh? This amazing act of displacement is never really explained. Several 3rd season episodes had such nonsensical contrivances to the plot: this seems an excuse to have a separate storyline on the ship while the landing party struggles to survive on the planet. But, they're zero for two in this one: neither the 'A' or 'B' storyline is up to snuff - slow going in both.
On both the planet and the ship, the crew are stalked and killed by what seems to be a female hologram (Meriwether); they don't refer to it as a hologram, but that's what it seems like to me - an early version of the holodeck from the TNG show. This female disrupts all the cells of a body simply by touching that person; she announces beforehand who she's for, i.e. "I am for you, James Kirk" (the meaning is not what Kirk hopes for). Spock is never more annoying than in this episode; in command of the ship for most of the episode, he takes every opportunity to lecture the other crew members on how illogical they are. This does turn out to be an intriguing comparison to how the ship is usually run (by Kirk). Check out Uhura's annoyed expression when he lectures her about gambling. Dr. M'Benga is back (see "A Private Little War") - I guess he's Doc#2 on the ship. "My guess would be valueless" Spock tells him, almost in anger. And, of course, Spock's verbal attacks on Scotty are never ending; I'm surprised there were no whispers of mutiny by the time they got back to the planet. This repartee is all mildly entertaining but the story is tedious overall, with no interesting revelations about the ancient outpost of a planet or the attacking femme fatale.
On both the planet and the ship, the crew are stalked and killed by what seems to be a female hologram (Meriwether); they don't refer to it as a hologram, but that's what it seems like to me - an early version of the holodeck from the TNG show. This female disrupts all the cells of a body simply by touching that person; she announces beforehand who she's for, i.e. "I am for you, James Kirk" (the meaning is not what Kirk hopes for). Spock is never more annoying than in this episode; in command of the ship for most of the episode, he takes every opportunity to lecture the other crew members on how illogical they are. This does turn out to be an intriguing comparison to how the ship is usually run (by Kirk). Check out Uhura's annoyed expression when he lectures her about gambling. Dr. M'Benga is back (see "A Private Little War") - I guess he's Doc#2 on the ship. "My guess would be valueless" Spock tells him, almost in anger. And, of course, Spock's verbal attacks on Scotty are never ending; I'm surprised there were no whispers of mutiny by the time they got back to the planet. This repartee is all mildly entertaining but the story is tedious overall, with no interesting revelations about the ancient outpost of a planet or the attacking femme fatale.