Last time on DS9, the Klingons went to beat up the Cardassians and take their lunch money. Gowron invited Worf along. Worf turns him down. An argument over honour ensues and Gowron excommunicates Worf's family. Wow. Over-reacting much? Just because he won't drop everything to come along on your little jaunt to beat up the Cardassians?
O'Brien finds Worf moping in Quark's bar, and Worf says he wants to resign from Star Fleet. O'Brien says they'll build a new Enterprise (this presumably being a reference to Generations), but Worf says the uniform reminds him too much of his Klingon pals kicking him out. Then Quark comes over and makes a racial slur about Klingons, making Worf leave. Sisko's not enthusiastic about accepting Worf's resignation though. Kira says that the Klingons have broken through the Cardassian fleet, and Worf points out this will mean that they'll execute the Cardassian government. Sisko contacts Dukat re getting all the Cardassian government to safety before that happens.
Before leaving in the Defiant, Sisko puts Kira in charge and chats with Kasidy. Awww, those two are cute. They set off, though Bashir finds it necessary to remind Sisko that their agreement with the Romulans means they're not supposed to use the cloaking device in the Alpha quadrant. Before long, they find a mass of destroyed Cardassian ships, but can't scan for survivors while cloaked. Eventually, they find Dukat's ship under fire by Klingon ships.
After warning the Klingons to stand off, one of the Klingon ships fires on them, so the Defiant chases them off, destroying one of them. Unfortunately another larger Klingon ship arrives. Worf uses a modified tractor beam to redirect some of the ship's fire while they transport people from the Cardassian ship aboard with the shields down. They set course for DS9, though Dax reports the cloak is down.
Gosh, this is actually exciting!
Bashir screens the blood of all the evacuees to make sure they're not Changelings. Dax apparently had a bet with Sisko that Dukat would start complaining before thanking Sisko for the rescue (he does). Ha!
Back on DS9, Quark presents Garak with some Cardassian drink, which he has cases of in storage and has just realised he's never going to unload. Then Quark compares the Federation to root beer.
Sisko radios ahead to let Kira know they're bringing company back with them. Quite a lot of the Klingon fleet, in fact. The Defiant arrives back to find a dozen Klingon ships waiting. Uh oh!
O'Brien says that a relief force is on the way, but won't get there soon enough. Sisko announces brown trouser alert. Preparations are made.
Martok demands that the Cardassian council members be turned over to them. Sisko tells them to sod off. Thus the attack begins. After a bunch of Klingons ships are destroyed, they manage to knock out a couple of the station's shields and start transporting aboard. During the fight, Kira is stabbed, but still manages to beat up the Klingon who stabbed her. O'Brien manages to get the shields back up, and Odo says he's contained the boarding parties. Dax reports the Federation ships are getting close. Sisko and Worf talk some sense into Gowron, and he stands down the Klingon fleet, but says he won't forgive them for siding against them in battle.
With the Klingons gone and the station undergoing repairs, Sisko talks Worf into staying on the station as strategic operations officer. Also, though the Cardassian government has returned home, the Klingons are refusing to give up some of the colonies they ceased.