The Breen have entered the war, and they hit the Federation where it hurts: Earth. What's worse, they have developed a new weapon that drains all energy from a ship, and not even the trusty Defiant can withstand it. On Bajor, Kai Winn finally completes her FaceHeelTurn, while on Cardassia, Legate Damar does something that even the Founders never saw coming.

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!!This episode contains examples of:

* AbandonShip: The crew of the ''Defiant'' is forced to do this before she's destroyed.
* ApologyGift: Sisko gives Kassidy flowers to apologize for trying to get her off active duty after the Breen attack.
* BloodMagic: How the ''[[TomeOfEldritchLore Text of the Kosst Amojan]]'' is revealed.
* CurbStompBattle: One of the worst the Federation suffers in the war.
* DramaticallyMissingThePoint: When Weyoun sees Damar not holding a bottle, he assumes that Damar has grown to accept the Dominion. In reality, it's because Damar has decided to form LaResistance.
* EnemyMine: The Federation isn't exactly friendly with the Cardassian Union, but at this point they'll take any help they can get.
* FaceHeelTurn: Kai Winn. Granted, she was never quite a good guy to begin with, but this episode makes it official.
* HeelFaceTurn: Legate Damar has finally had enough.
* InsistentTerminology: It's not a ''toy''; it's a ''model'' of the Alamo.
* LaResistance: This episode is the beginning of the Cardassian uprising.
* MonumentalDamage: The Golden Gate Bridge.
* MyGodWhatHaveIDone: When Winn learns that she's been consorting with Dukat, she looks like she's about to throw up.
* OhCrap: The ''Defiant'' crew's reaction to the Breen weapon. As well as to the attack on Earth.
** The Dominion's reaction to Damar's rebellion. Weyoun, in particular, knowing that he's the last clone. And knowing that's ''exactly'' why Damar targeted the cloning facility.
* OneHitKill: The ''Defiant'' of all ships is fried in one hit. Of course, it takes a number of hits from more practical blasters to outright destroy it.
* PowerNullifier: The Breen's energy dampening weapon.
* ProperlyParanoid: Weyoun does notice that Damar's attitude and demeanor have changed, saying he emerged from a dark tunnel and into the light. Of course, he's completely wrong in how he interprets it.
* ShootTheShaggyDog: The sacrifices of the defenders of [[StarTrekDeepSpaceNineS07E08TheSiegeOfAR558 AR-558]] are rendered pointless as the Dominion retakes the Chin'toka system and the comm hub on the planet.
* SinkTheLifeboats: Weyoun suggests doing it to the Federation Alliance, but the female changeling overrules him. Not out of any sympathy but because she needs survivors to spread fear of the Dominion's new superweapon.
* SpareAMessenger: The female Founder countermands an [[SinkTheLifeboats order to destroy]] the {{Escape Pod}}s, saying the frightened survivors will return home and spread their fear, demoralizing the enemies of the [[TheEmpire Dominion]].
* TomeOfEldritchLore: The ''Text of the Kosst Amojan'', which Winn and Dukat need to release the Pah-Wraiths.
* TheUnreveal: Weyoun says that all the stories about the Breen homeworld being a cold wasteland actually aren't true. When Damar asks why the Breen wear refrigeration suits, Weyoun just shrugs.
* WhatTheHellHero: Cassidy chews Sisko out for getting her taken off the active list.
* TheWorfEffect: The ''Defiant'' bites it to show that the Breen mean business. Of course, [[TropeNamer Worf]] ''is'' on the bridge when it happens...
* WorthyOpponent: Martok is rather impressed by the Breen's audacity in attacking Starfleet Headquarters.
-->'''Martok:''' Even my people never attempted that.