Nutshell: Superficial action fun taken to the most relentless of extremes—and it works.
Once again, DS9 takes us to the mirror universe where we follow the rebellion and their struggle against the evil Alliance. Two seasons ago—the first time DS9 took us to this parallel universe in "Crossover"—the premise sported a dark, somewhat brooding attitude. Last season in "Through the Looking Glass," the dark undertones were significantly reduced, and an adventurous romp took center stage. With "Shattered Mirror," DS9 takes the premise yet another step into full-blown insanity. The episode has its semi-serious moments, but for the most part it's a completely over-the-top, superficial, comic book adventure—even more so than "Looking Glass" was.
I'd be lying if I said "Shattered Mirror" is a standout accomplishment in skilled writing or character development—it's not. But I'd also be lying if I said this show isn't a gleeful diversion. It's good comic book—big, dumb, sensationally simplistic, and fun.
The premise? Well, like any comic book, it's about good versus evil. More specifically, the mirror version of Jennifer Sisko comes to "our" side and kidnaps Jake to the mirror side. Sisko crosses over to retrieve his son, and finds himself kidnapped by the rebellion and enlisted to help them. "Smiley" O'Brien brings him up to date on current events (the rebels have driven the Alliance off of Terok Nor, claimed the station for themselves, and imprisoned Intendant Kira). O'Brien insists Sisko help them put some necessary finishing touches on the Defiant they have built (courtesy of some stolen schematics from DS9 on the other side).
Time is a big factor. In a matter of days the Alliance's reinforcements will reach the station, and if the rebellion doesn't have a reasonable weapon to defend themselves by then, they will surely be recaptured.
The plot (what little bit of it there is) takes a while to get fully underway, but when dealing with mirror characters, that's all the better. In all honesty, even if this show had nothing going for it other than its reversed role-playing, it would probably still be worth watching simply because of the opportunity to see the cast in neat costumes while delivering enjoyable dialogue.
The episode's first four acts center around the Preparation for the Battle between Good and Evil. Mired in here somewhere is a somewhat interesting angle involving Jake's fascination of meeting his "mother" and his kid-like misconception of realism. He gets caught up in this fantasy-like world, and seems blind to the dangers of it.
Meanwhile, Sisko assists in preparing the Defiant for combat as we again meet the other mirror characters, many of whom are not happy with Sisko's masquerading as their leader the last time he was in their universe. Bashir hits him in the face. ("I owed you that.") Dax slaps him in the face and pulls a knife on him. ("That's for making love to me under false pretenses.") Intendant Kira is, naturally, her same libidinous self, and believes that a Ben Sisko is a Ben Sisko. She considers supplying him with information about the Alliance in exchange for...you know. ("Why don't you lower this force field and join me in here—might help stimulate my thought process.")
At the same time, the Alliance's reinforcements continue steadily on their way to Terok Nor. They are commanded by (surprise!) Regent Worf, who is quite angry with Garak for his retreat from Terok Nor. The writers' portrayal of Worf as the villain is about as unsubtle as it gets. He puts a collar around Garak and attaches it to a chain which he uses to pull Garak around like a pet on a leash. Much of the subplot has little to do with advancing the plot, but the results are so often funny (and always laughable) that they're well worth the screen time. Such scenes wisely never show any hints of taking themselves seriously. Worf has some amusingly goofy lines to Garak. ("You are not my type" and "Make it so!" come to mind.) Garak, as always, is a fountain of clever wording worthy of a chuckle in just about every scene.
And Intendant Kira is as fun as usual with some memorable sound bites like "Violence is a precision instrument—it's a scalpel, not a club," and her amusing double-entendres. And when Nog breaks her out of prison she repays him like any villain would—she kills him. Still, one of my favorite lines in the show is her deadpan, ever-so-slightly annoyed delivery of "That was unfortunate," after she accidentally phasers Jennifer while aiming for Jake. Cold, yes; but still funny.
The show's final act is The Battle, when the Alliance fleet reaches Terok Nor and opens fire. Fortunately, the Defiant is ready just in time for the big fight (in which, naturally, they triumph, as Worf orders retreat as his ships are destroyed).
The battle supplies an absolutely beautiful special effects display featuring some very impressive motion photography work. (In fact, I bumped the rating up an extra half star because of it.) The scene uses the station as a battlefield where Birds of Prey and the Defiant weave in and out and around the architecture at breakneck speed, shooting at one another. Dan Curry and his crew have produced some of the most eye-pleasing action movements of probably any of Star Trek production. Then they outdo themselves just minutes later when the Defiant takes on Worf's battle cruiser (which is dozens of times the size of the Defiant) by getting in close to do some damage with moves surely inspired by the Millennium Falcon. In a word: Wow. These effects harbor even more speed and style than both "The Die is Cast" and "The Way of the Warrior" did.
The scene works on two levels. Aside from creating a sheer appreciation for the quality of the effects, the movements are fresh demonstrations of tactics. What should Sisko do when he's outgunned by a big ship? Why, take his little ship within inches of it and toy with their targeting, of course!
The only serious moments in "Shattered" are toward the end, where Jennifer's phaser wound results in her death, forcing Sisko and Jake to relive her death a second time. Her deathbed scene is nicely done, although it seems maybe a tad out of place considering how non-serious the rest of the episode feels. Not too bad in any case.
Between Kira's intention to "collect a debt" from Sisko for sparing his son's life, Worf's vow to return and destroy all the rebels, and Garak's plot to capture and punish Kira for her "treachery," I'd say the chances of the DS9 characters visiting the mirror universe again (or vice versa) are approximately 100 percent.