By Any Other Name
Passengers on a scout ship from the Andromeda galaxy hijack the Enterprise. Yet to run it, they must take human form, and the remaining officers find the beings' only weakness is sensory stimulation.
At last we have aliens with the power, motivation, and determination to overtake the ship. Unlike the numerous hijackers in the third season, these guys are totally convincing. The Enterprise travels further than it's ever been (and will ever go again) as it races to the Andromeda galaxy. Spock and Scotty's plan really emphasizes the seriousness of the situation, but of course Kirk doesn't carry it out. But then - it becomes a comedy? Okay. The latter half of the show is actually quite funny, but it seems a bit of a shame when they had such a tight, tense drama going earlier. But we can hardly forget moments like Scotty getting sloshed on whisky and that "green stuff", Spock's carefully chosen words to rile up Rojan, or Kirk kissing... actually, that's pretty common. The captain's "I'm stimulating him!" as he and Rojan fight sums up things well. Peace is achieved a bit easily, but overall this is quite an enjoyable installment.
Spock Saves the Day: Spock learns about the aliens via mind touch, rigs the ship to explode (on the captain's orders) as they cross the outer rim of the galaxy, and makes Rojan aware of Kirk's affections for Kalinda.
Oops: After Charlie X you'd think Spock would know not to best superior beings at chess, but some things are irresistible.
Developments: An interesting variation on the "mind touch" is seen when Spock is thrown several feet by the force of these aliens' minds, as will happen even more intensely in The Motion Picture. His self-induced trance is plausible considering his abilities relate to mind control.