Nutshell: The story is a collision of about four disaster movies, but the flawless plot assembly and impressive technical credits will make you forget the shortcomings.
Sisko and crew take the Defiant through the wormhole to meet the Karemma, the financial experts of the Gamma Quadrant. The Dominion disapproves of the meeting between their cash runners and the Federation, and sends the Jem'Hadar to "punish" the Karemma for their disobedience. In an attempt to protect the Karemma, the Defiant ends up in a battle with the Jem'Hadar inside the violent atmosphere of a nearby planet.
From a storytelling standpoint, this is probably the weakest episode so far this season (except for "Little Green Men," but that was a comedy). Fortunately the episode transcends its basic storytelling with some good suspense scenes and lustrous showmanship.
On a technical level, "Starship Down" is an outstanding episode. The several battle scenes inside the windy, cloudy atmosphere boast some absolutely superb special effects with feature film quality. And if you like to see sets explode, you're in for a treat, because just about every Defiant location becomes the victim of pyrotechnic rigging.
The plot is a collection of elements that were seemingly inspired by a disaster movie, if not four disaster movies. With the ship severely damaged, key members of the crew become isolated from each other, and the episode becomes a number of sub-stories, including (A) Worf taking control of the ship from engineering so he can elude the Jem'Hadar; (B) Kira trying to keep an injured Sisko from falling unconscious and dying by telling him a story; (C) Quark and the Karemma trader Hanok (James Cromwell) discussing the ethics of trade while disarming a torpedo which has punched through the hull; and (D) Bashir and Dax locked in an isolated corridor of the ship with no life support. It sounds ridiculous, but by some extraordinary feat of plot engineering, these sub-stories all come together and work as well as they possibly could have.
This type of crosscutting and scene changing makes writing an economical synopses fairly nightmarish. I guess the best way to do this would be to look at each sub-story individually. Bear with me here...
(A) Worf taking control of engineering shows how much he has to learn about command. In a crunch, Worf wants results within seconds after he barks an order. He isn't wrong-headed—he just doesn't understand that under the circumstances his crew is only capable of so much; and he is not very tolerant when his demands can't immediately be met to the letter. This leads Chief O'Brien, speaking from experience, to tell Worf that engineers need to be given problems to solve, not concrete orders to obey. I like the fact that Worf makes mistakes—that he isn't the perfect commanding officer. It makes his situations more realistic and the character more interesting. Worf, being reasonable of course, heeds O'Brien's lesson. As a result, the ending—in which Worf hands the engineers a problem to solve, allowing the Defiant to cleverly trick and destroy the Jem'Hadar ship—displays cool-headed style and finesse.
(B) As Kira tries to keep Sisko from slipping into a coma, we again see Kira torn between seeing her superior officer as just a co-worker she respects or a religious icon for her people. This is an element of the series that is always welcome, and it's nice to see that the show remembers and cares about its history and wants us to as well. Unfortunately, things get a little bit repetitive, and this idea was already done in the far-superior "Destiny" last season. The only new element here is Kira telling Sisko that she regrets they have never spent any real off-duty time together as close friends. Unfortunately—and this is the biggest missed opportunity of the episode—the show's closing scene on the station between Sisko and Kira is far too cheery and hokey to really be poignant; it consequently undermines most of what this tries to accomplish.
There's also the question of the chain of command aboard the Defiant. It seems Worf takes command of the ship before Kira. I don't quite understand why this is since the episode doesn't take time to explain it, but at least it gives Worf something to do in addition to being the genesis for the Sisko/Kira scenes.
(C) Hanok, meanwhile, is angry at Quark for cheating him in the Karemma/Federation negotiations. To ease tensions, Quark chummily introduces Hanok to the excitements of gambling and financial risk and gain. This plotline is played mostly for laughs, and works surprisingly well. Even more surprising is how much suspense director Alexander Singer is able to milk out of the scene where they must disarm the torpedo, yet how hilarious Quark's solution to the problem proves to be. Not bad at all.
(D) Dax and Bashir trapped alone is just an excuse for gratuitous cuteness. This bit falls flat. Anyone who watches the series regularly knows the "just good friends" relationship these two have. The subplot isn't necessary beyond the need for filler to give the two characters a purpose in the latter acts of the show. However, the way the two get into the situation in the first place is nice. I like Dax's heroics of trying to repair damage when she's aware her section of the ship is about to be sealed off. Also, Bashir's actions to come to her rescue gives him a chance to show initiative.
All in all, "Starship Down" manages to work somehow. It's the best case scenario of the sum of its parts. It doesn't mean a whole lot (in particular, exchanging fire with the Jem'Hadar will apparently have no direct political consequences). Yet the episode is a decent adventure outing that looks great. Good execution and, although not all the characterization is on target, everything holds together.