The Enterprise saves a decrepit ship from crashing on planet Ornara. During the rescue, the doomed freighter inexplicitly sends over cargo before bothering to help the Enterprise save their crew. Two of the crew die because of this. The cargo turns out to be "Felicium," a medicine for Ornarans. Except, actually, it's an addictive narcotic. The two Brekkans saved from the freighter already know felicium's nature and are a bit nervouse that Picard will interfere with their trade by telling the Ornarans. Picard refrains because of the prime directive, which of course upsets Dr. Crusher. But he also refuses to help fix Ornara's other freighters, essentially abandoning the Brekkans on Ornara with the soon-to-be consequences of their dishonesty. The episode ends with the expectation that when this shipment of felicium runs out, all the Ornarans will experience withdraw and discover the true nature of the "medicine" the Brekkans have been selling them for generations.
I can't believe I'm saying this, but... Wesley made me cringe. It was at the end of the episode, but I had to mention it before I conveniently changed my mind. See, Tasha gives him the best short explanation about drug use in the history of mankind, and at the end Wesley quirks an eyebrow and says "I guess I just don't understand." I know he's supposed to be sheltered an an ultra nice kid and all, but that line and its delivery were just... Gag. The cynic in me won this round.
Whew. Glad I got that out of the way because it's also my only real complaint about the episode. The drug thing was nicely foreshadowed, and afterwards nicely explained. The best part, of course, is that those pricks will be stuck on the planet when it runs out of drugs and the withdrawls start. Whether they spill their secret or not, they're screwed.
And the line Picard gives Dr. Crusher about humans trying to help and always fouling it up? Spot on, Picard. Spot on. The truth behind that is one of the reasons I can stand the Prime Directive at all even though I'm not an Isolationist. There's something to be said for always thinking that you know what's best for other people, and being generally wrong. Studying South American history and the endless times that the US has or has tried to help - well, let's not get into that. Let's just say that sometimes there are no good choices and unintended consequences bite. Like cats in Australia.
But hey, at least we aren't knowingly, as a planet, dishonestly operating as drug dealers for another planet. That's low, man. They're just lucky they didn't threaten to kill Wesley or something, because then Picard might have had to kick their butts.