A task force of Klingon ships commanded by General Martok
camps out around DS9 to await a potential Dominion incursion through the wormhole. Tensions rise as the Klingons throw their weight around: a gang of them beats up Garak, and Klingon ships begin boarding and searching other vessels for changelings without cause. Captain Sisko decides that the best way to handle Klingons is with another Klingon, so he sends for Lieutenant Commander Worf. Worf challenges Martok by slapping around his son, and learns that Sisko's suspicions are correct: there's something else going on which Martok suggests could determine the future of the Klingon empire.
Worf convinces a friend of his father to tell him the whole story: the Klingons believe Cardassia has undergone a Dominion-engineered coup, so they are preparing to invade Cardassia themselves. The Federation opposes the move, but Chancellor Gowron and the Klingon High Council go ahead despite the harm it could cause to the Federation-Klingon alliance.
Sisko "accidentally" lets Garak overhear a discussion about the attack, so he can pass the information along to the Cardassians. It seems the Klingon fears of Dominion influence are unwarranted. The Federation condemns the attack, so the Klingons end their peace treaty with the Federation. Gowron arrives at the station and invites Worf to join him, but Worf refuses to abandon his Starfleet post, so Gowron strips his family of their lands and honors.
Sisko contacts Dukat (now military advisor to the new civilian government of Cardassia) and offers to help him get the Cardassian council members to safety. After a large battle, they get the council on board the Defiant and head for home, pursued by a large Klingon fleet. This brings us to an impressive battle sequence
as the station (armed with 5000 photon torpedoes and multiple phaser banks) holds off the Klingons until reinforcements arrive. (This was also the last battle in the whole Star Trek
franchise to use models rather than CGI, which makes it an especially impressive achievement for the special effects team.)
The Klingons back off, but make it clear that they do not
forgive and forget. Worf goes through some soul-searching, but decides to stay in Starfleet and becomes DS9's new Strategic Operations officer.
- Armor Is Useless: Averted—the Defiant's ablative armor protects her while her Deflector Shields must be lowered for transporter use.
- Badass Boast: Dax, when Worf warns her that a bat'leth duel between them wouldn't be a fair match: "I'll go easy on you." Even though she loses, she still lasts longer than Worf probably expected.
- Batman Gambit: Worf approaches Martok's son, Drex, at the bar, immediately beating him up and taking his d'k tahg. He did this because he knew it'd force Martok to come to him.
- Big Badass Battle Sequence: Both the Klingon fleet and the station combine Beam Spam and Macross Missile Massacre.
- Brick Joke: Early in the episode, Drex and his buddy harass Morn. Several scenes later, Drex causes trouble at Quark's and Morn hastily leaves.
- Callback: When trying to get Worf to play darts, O'Brien likens the game to poker—a game regularly played by Worf and others on TNG.
- Casual Danger Dialogue: Garak and Dukat while fighting Klingons:
Garak: I find this hand-to-hand combat really quite distasteful!
Dukat: I suppose you prefer the simplicity of an interrogation chamber!
Garak: You have to admit—it's much more civilized!
- Chronic Backstabbing Disorder: Dukat is now a part of what he was quick to acknowledge as Cardassia's wholly legitimate new civilian government because—as Sisko puts it—he "saw which way the wind was blowing and switched sides."
- Continuity Nod: When Sisko warns the Klingons about the station's armaments, Gowron and Martok suggest it is an illusion created by thoron fields and duranium shadows. Both the weapons figures and this Techno Babble fakery method come quoted from the pilot episode, Emissary, when O'Brien really did fake their presence in this way. But now, three years later, the station really does have all that weaponry.
- Curb-Stomp Battle: Worf effortlessly stomps Drex. The first step in casting off The Worf Effect.
- Death Glare: Worf gives Quark one for laughing at his Drink Order of prune juice and another later when Quark says he's glad that they're rid of all the Klingons.
- Enemy Mine: Garak lampshades it when he and Dukat are forced to work together to fight off Klingons.
- Fake Action Prologue: The episode starts with half the main cast and several redshirts hunting a changeling infiltrator—who turns out to be Odo acting as said infiltrator during a drill.
- Gunship Rescue: Downplayed when Sisko and the Defiant rescue Kassidy Yates from the Klingons. (They only fire one warning shot before Kaybok backs down.) Played straighter when they rescue Dukat and the Detapa Council.
- Heroic BSOD: Worf turns out to have taken what happened to the Enterprise pretty hard—to the point where he intends to resign from Starfleet.
"It will not be the same. The Enterprise I knew is gone. Those were good years, but now it is time for me to move on."
- "Hey, You!" Haymaker: How Worf introduces himself to Drex right before kicking his ass.
- Honor Before Reason: Though he had admitted feeling out of place since the Enterprise's destruction, Worf refuses to join in Gowron's invasion plan because he thinks it's wrong and because he vowed allegiance to the Federation. Even when threatened with being stripped of his land and privileges, Worf responds that he will always have his honor.
"It is not what I owe them that matters; it is what I owe myself. Worf, son of Mogh, does not break his word."
- I Choose to Stay: After convincing Worf not to resign, Sisko offers to pull some strings and get him transferred to the Venture. Worf says that won't be necessary.
- In Vino Veritas: Worf uses a little song and bloodwine to get one of the Klingons to tell him the truth about Martok's task force.
- It's Quiet... Too Quiet: Quark says this with a bar full of Klingons not partying like they usually do. It's the first hint that something serious is up.
- Kick the Dog: A few Klingon thugs harass Morn For the Evulz.
- Macross Missile Massacre: During the battle between the station and the Klingon armada, DS9 becomes this. Torpedoes... torpedoes everywhere.
- Major Injury Underreaction: A group of Klingons gang up on Garak, putting him in sickbay.
Bashir: They broke seven of your transverse ribs and fractured your clavicle.
Garak: Ah, but I got off several cutting remarks, which no doubt did serious damage to their egos.
Bashir: Garak, this isn't funny.
Garak: I'm serious, Doctor. Thanks to your administrations, I am almost completely healed, but the damage I did to them will last a lifetime.
- Mythology Gag: Worf's transfer involves switching from the gold uniform to red. On TNG, he wore red in Season 1 and switched to gold in Season 2.
- Nice Hat: A literal use of the phrase by Worf to Kira, who meets him on emerging from the holodeck wearing a Middle Ages dress with a huge two-pointed hat.
- OOC Is Serious Business: After their ships first arrive at the station, a bunch of Klingons go to Quark's and... don't make a sound.
Quark: Have you ever met a quiet Klingon?
- Pay Evil unto Evil: Worf beating up Drex, who had earlier harassed Morn and led a beatdown on Garak. Worf later tells Martok that he did know about the latter incident, and he notes other misdeeds Drex had participated in since the Klingons came to the station.
- Scylla and Charybdis: Sisko has to do this twice, both times choosing between the Klingons and Cardassians. In the first case it's whether to warn the Cardassians of the Klingon invasion, when Starfleet has ordered him not to. He takes a third option by 'accidentally' letting Garak eavesdrop on them discussing the matter. However, later he is forced to take a more direct decision - whether to rescue the Cardassian Detapa Council from the Klingons blasting away at their ship, and put 70 years of peace with the Klingons at risk. He does.
- Tomboy and Girly Girl: The holodeck scenes highlight the contrast between Dax and Kira. Dax enjoys getting a massage from Mr. Fanservice and playing a medieval princess, but Kira has to be dragged into it, with less-than-successful results.
- Took a Level in Badass: The station itself. O'Brien has spent the last three years turning it into a floating torpedo turret.
- Try Not to Die: Cassidy to Sisko before the latter goes on the rescue mission.
- Ungrateful Bastard: Dukat. Lampshaded by Dax betting that Dukat would start complaining before thanking Sisko for rescuing him.
- Wham Episode: Worf arrives on the station and the camera pans up from his feet to his face. His character develops much more deeply on this show than it could on TNG, and the show itself takes a more serious, arc-based direction at about this point. This is when the scope of the show expands to include all the familiar powers of the Alpha Quadrant, and it puts us on notice that anything can happen to the political situation between them.
Worf to Martok: You must think me a fool to make your lies so transparent!
- Wham Line: Sisko's "I've got five thousand photon torpedoes armed and ready to launch".
- "Seventy years of peace with the Klingons, and it all comes down to this..."
- The Worf Effect: A rare example for DS9. When Klingons beam onto the station, even the smallest humans and Bajorans knock them out left and right with as little as their bare hands.
- Worthy Opponent: Gowron and Martok speak of the station's crew as this (in Klingon; a bit of research is needed to translate it).
Martok: <They fight like Klingons!>
Gowron: <Then they can die like Klingons!>
- You Have Failed Me: Kaybok's fate, courtesy of Martok.
- Your Mom: Drex insulting Odo in Klingon, as suggested by Garak's reaction: "Actually, I'm not sure Constable Odo has a mother."