The latest in the Prime Directive series, call this "The Prime Directive Ignored, Played for Laughs." This episode is often cited as a fan favorite, and it's easy to see why. The tone is light, and the laughs are genuine. The cast gets to make the gradual transition to gangsters, and our characters are revealed to be competent actors in their own right. This shouldn't be a surprise. Running around the galaxy certainly involves acting for diplomatic purposes, and we have seen Kirk do this before.
But everything gets a little out of hand. Restraint is a very valuable instinct, and the Star Trek creative team usually maintains a certain level of decorum that is not present here. It's fun to see Kirk try to drive a car, but the joke goes on way too long, and then gets resurrected when they need transportation a second time. It's fun to see Scotty puzzled by the lingo, but this too gets overworked.
The fish-out-of-water aspect itself seems to take over the episode. There is not really a story here, just a collection of interesting scenes in which we get to see our heroes play gangster by donning 20's attire, driving Flibbers and handling machine guns. If anything, this episode is a pale remake of "City on the Edge of Forever" without the love story, or the interesting starting point, or the interesting resolution, or -- you get the idea.
Once again, the Prime Directive has failed as a dramatic device. Since the premise here is a breach of the non-interference principle, one might expect the episode to center around questions about how to repair the damage. The script hints at this by having Spock indicate interest in exploring the depths of the contamination. By having the heroes captured and subjected to blackmail (repeatedly), the characters spend all their time getting out of (and back into) trouble. Kirk's ultimate solution seems to come from nowhere, and has all the impact of a quick fix. Just what changed that allowed Kirk to simply take his phaser out of Bela's hand, despite the fact that machine guns are pointing at him (as they have been throughout the episode)?
Thinking too much is definitely the enemy here. But a little more thinking would have led to sharper jokes, restraint in the gangster portrayals, and a plot worthy of a concept as large as the Prime Directive.
Rating: Middle (4)