Spoilers ahead! If you haven't seen this episode and continue reading... It doesn't matter! The episode is just that good.
For those that haven't, and for those whose memory is fuzzy, a short synopsis:
A furious Major Kira confronts Quark about his hacking of various station systems to insert a jingle for his bar, with humor careening in at Worf's expense (a typical source). From there, it shifts to "routine mission" mode, with Kira, Doctor Bashir, and Dax doing something in the Gamma quadrant. They detect a distress beacon, and head towards it. They find a planet and people who have been ravaged by a disease called "the blight" for nearly 200 years. The inhabitants are born with the disease, and usually die before reaching 30. Doctor Bashir assumes he can cure it, and attempts to help. He inadvertently makes it worse, and almost runs away. Instead, he stays for an undisclosed amount of time on the planet and eventually discovers a vaccine, but not a cure. The episode closes with Bashir sitting in his office on DS9, trying combination after combination of nucleotide sequences to attempt to find a cure for the disease.
The power of this episode is that it encompasses everything great about Star Trek as a universe, as well as the potential of the "medium" that is Star Trek.
I'd forgotten about this episode until I recently watched it again. There's no giant action moment that stays with you, and if you're not completely focused, it's easy to peg it as a routine "save the people because we're awesome" episode.
It starts with a hilarious segment, which, aside from being entertaining, demonstrates that these characters have daily troubles, and daily minutia, just like us.
Everything between that and landing on the planet is a vehicle (literally, since they're on a runabout) for the plot.
The inhabitants explain to Doctor Bashir and Dax what happened: 200 years ago, they were an advanced society, just like Earth of the 24th century. At this point, you've already seen numerous examples of their current society; they barely survive, knowledge is lost as soon as it's gained (people die too early in their lives, often before their children are old enough to remember them), doctors are practically mythological, and they've begun to worship death instead of life (because life is so painful with the blight). Immediately, you're slapped with the obvious: this could be Earth, this could be OUR Earth. There is nothing really stopping a plague from retarding our entire society, tomorrow. This is scary!
Bashir immediately demonstrates how powerful and yet destructive hubris can be. His hubris in assuming he'll find a cure is embarrasing, even for the audience. He tries to soften this with, "I make no promises," but it's clear that's he's acting like he's already found the cure, that it's inevitable. While it's easy to say that this is just Bashir being arrogant, this is actually a microcosm of both the attitudes of The Federation as well as humanity. And not just Star Trek's idea of humanity, this is us. Even more specifically, this is an American attitude: we are invincible, and with enough effort, we or even an individual can do anything.
Eventually Bashir gains enough trust and inspires enough hope in these desolate people that they offer to be his guinea pigs as he attempts to find a cure. Soon after his first attempt at the cure, nearly everyone in his clinic suddenly dies, very loudly, and very painfully. The blight apparently began mutating cumulatively due to the electromagnetic radiation from Bashir's high-tech instruments, the very instruments that were supposed to help him find a cure.
Bashir is devastated, the unexpected death of his patients has leveled him below grade. He realizes how arrogant he has been, but Dax quickly corrects him with a stimulating punch to the gut:
Maybe it was arrogant to think that. But it's even more arrogant to think there isn't a cure just because you couldn't find it.
This encouragement forces Bashir to right himself, and he decides to stay on the planet by himself while he works on a cure. He finally realizes that this is going to take work, and won't be a quick fix with immediate glory.
He ends up finding only a vaccine (meaning it can only be given to those not infected with the blight, i.e. newborns), and even that is an accident. While this will effectively allow the society to right itself in a generation or two, it's clear that Bashir still considers the endeavor a personal failure.
Bashir rightfully considers this a personal failure, because he let his own arrogance get in the way of his work. But this failure goes deeper than that in his mind, and is an ingenious example of both the danger and the power of infinite confidence. Technically, he was successful: he saved future generations from the blight. But this is not what he defined initially as success, which was finding a cure, saving everyone, and getting all the glory. Even though others would consider a vaccine a success, Bashir is so arrogant that he believes that his is the only proper definition. He saved an entire race of people from a life of pain and suffering and oppression! But he can't accept it, because it's not what he defined as "winning" the problem.
As the episode closes, and we see Bashir effectively throwing darts on the wall relentlessly trying to resequence nucleotides to find a cure, one can't help but wonder if his unstoppable confidence is an asset or a curse.
And this is why this episode is perfect: it simultaneously shows the positive potential of humanity as well as all of the things that we try to push out of our lives: hubris, unbridled confidence, unrealistic determination, and the yearning for recognition. All while being entertaining and extremely well-acted.
There isn't a single space battle. The only special effects are the transporter sparkles and a stock shot of the runabout banking. This is Star Trek at its finest: an episode that could have been filmed today, 50 years ago, or tomorrow. The human descriptions outlined here are ones that both haunt and drive us to great heights. The lens of Star Trek has the potential for an amazingly sharp view of ourselves.
— @KirbySaysHi Sep 22, 2013