"We do not colonize. We Conquer! We Rule!" Guess we know where these Kelvans stand, don't we? Or, perhaps not. For, they have taken human form. Actual Kelvans are 'immense beings' with a hundred tentacles. Such beings would have problems with a turbolift (and sixties FX would have problems depicting them). So, hearkening back to the aliens of "Catspaw" and "Return to Tomorrow," these Kelvans have set themselves up for major seduction trouble by assuming our treacherous human form. And, strictly speaking, they're not invaders, merely an expedition force on its way back to the Andromeda Galaxy, where radiation levels will make life impossible there in about 10,000 years. Once back home, they'll tell the rest of the Kelvans to go ahead and proceed to our Milky Way galaxy and then conquer the hell out of it. But, the Federation would have no immediate worries; the invasion force probably won't arrive for at least 600 years (the round trip). If they ever create a Trek show set in the 29th century (or even the 26th), there's at least one story arc ready to be used.
So, I'm not sure why Kirk and his officers were so worked up. Of course, their personal situation was a bit grim: the prospect of being stuck on the Enterprise for the rest of their lives as it hurtles towards Andromeda is kind of a downer. Though there are only half-a-dozen of these Kelvans, they easily take over the ship with their paralysis field weapons. They also modify the ship's engines. We're back at the galactic barrier first seen in the 2nd pilot episode, "Where No Man Has Gone Before" - and through it. Then most the crew are turned into small weightless tetrahedron-like blocks. When I first saw this as a kid, a genuine chill ran thru me when one these blocks was crushed to dust, thereby killing a crew member in a rather horrifying manner. This was super-science employed as a war tactic, as an instrument of terror. This was alien invasion thrills and chills, no doubt, and these Kelvans seemed a step up from the usual baddies encountered on the original show (Klingons, Romulans, etc).
But then, as was customary with many episodes after the first season, a grim tone changes to a playful one in the 2nd half of the episode. Then we get games of seduction and inebriation, of Kirk, Spock, McCoy and Scotty using their wits rather than their brawn, though in a manner befitting a Marx Brothers comedy instead of a sf adventure. It's still entertaining, sure, but I would have preferred some payback for that first half of terror, and the episode is rather uneven as a result of the precious ploys. The sugary ending is so cloying, so convenient, I usually need a shot of Scotch to get rid of the taste. On the plus side, Kelinda (Bouchet) is probably the sexiest alien we see on the original show and Kirk's super-stud status was assured with this episode. Scotty has the best scenes - it's green, indeed - and rumors of his alcoholism might have started here. And those images of the Enterprise zooming towards another galaxy stay in the mind for awhile. This imagery was repeated in the 3rd season's "Day of the Dove."
