A distress signal from the Gamma Quadrant reveals Enabran Tain may still yet live. And the search to find him exposes secrets that are about to spell trouble for the Alpha Quadrant.
- Callback: Bashir attempts blood screenings on each of the prisoners to make sure they're not Changelings, but he admits they could very well be useless. The Changeling that replaced Martok successfully beat a blood screening in "The Way of the Warrior". He also points out he can't test the Breen, because the Breen do not have blood.
- The Changelings being able to fool the Blood Tests are also a subtle callback to ''Homefront'', when Joseph Sisko cast doubt on their accuracy and hypothesized how a clever Changeling could get around them.
- Casual Danger Dialogue: Garak blithely asks a Jem'Hadar soldier for directions back to the wormhole. Said Jem'Hadar answers by slamming the butt of his rifle into Garak's face.
- The Comically Serious:Garak: Mr. Worf, you're no fun at all!
- Continuity Nod:
- Attempted. Sisko mentions "the recent Borg attack," no doubt a reference to Star Trek: First Contact. However, the stardate of this episode is actually before the film.
- The plan to close the wormhole is based on a technique developed by Lenara Kahn, Jadzia's ex (and the wife/widow of one of her past hosts) from "Rejoined."
- Darkest Hour: The Federation is still picking up the pieces from the recent Borg attack, the Klingons and Cardassians are both depleted from fighting with each other, and the Romulans aren't in much better shape.Sisko: The Dominion picked a perfect time to invade.
- The Darkness Before Death: Tain has gone blind in his final scene, minutes before he dies.
- Description Cut: Bashir wonders what dastardly scheme the Founder impersonating him is up to on the station. Turns out he's delivering a snack to the late-working Dax and O'Brien.
- Enemy Mine: A human, two Klingons, two Cardassians, at least two Romulans, and a Breen working together to escape. It doesn't get much more "enemy mine" than that.
- Foreshadowing: Dukat assures Ziyal that "Things are going to change on Cardassia."
- God Help Us All: Sisko's reaction to an impending Dominion invasion.
- Godzilla Threshold: Collapsing the wormhole. Nobody wants to do it (especially with Worf and Garak still in the Gamma Quadrant), but it's the best way to stop a Dominion invasion.
- Hope Spot: Using the main deflector to collapse the wormhole. It would've worked, if not for a certain Changeling infiltrator.
- I Have No Son!: Even on the brink of death, Tain initially refuses to acknowledge Garak as his son, though he relents. It differs from the usual use of the trope in that Tain isn't disowning Garak but, Consummate Liar that he is, is simply denying the fact that Garak even is his son, and Garak is only able to make him relent by pointing out that, being mere minutes from death, there's no need to keep up the lie any longer.
- It's All About Me: Dukat concludes that Kira has allowed Ziyal's friendship with Garak because she knows it will anger him. (He also refers to caring for his daughter as a favor to him, and doesn't register Kira's correction that it's about Ziyal.)
- Let Me Get This Straight...: When Garak invites Bashir to accompany him to the Gamma Quadrant and BS an excuse to Sisko on why they need a runabout.Bashir: So let me get this straight. You want me to lie to my commanding officer, violate Starfleet regulations, and go with you on a mission into the Gamma Quadrant which will probably get us both killed?
Garak: I'm ready when you are.
Bashir: In that case, let's go. (aims his phaser at Garak) To Captain's Sisko's office.
- Lost in Transmission: Played with. A great deal is lost in the last message sent by Garak and Worf, but there's enough there (including the final word "imminent"), combined with the loss of their various sensor probes in the Gamma Quadrant, for the crew to realize the Dominion is coming.
- Mass "Oh, Crap!": The entire crew realises that the Dominion is coming, and coming in force.
- The Mole: The Bashir on the station is actually a Founder.
- Not Quite Dead: Enabran Tain is revealed to have survived the disastrous attack on the Founders' homeworld. General Martok is also revealed to be alive after his Changeling replacement was discovered and killed in the season premiere.
- Oh, Crap!: Garak and Worf try to sneak through Dominion territory by flying through a nebula, only to find a massive fleet moving out.Garak: [eyes widen in genuine fear] Maybe this wasn't such a good idea after all.
- Overprotective Dad: Garak is nearly tossed off the second level of Quark's when Dukat catches him and Ziyal having lunch.
- P.O.V. Cam: The camera cuts to Garak's point of view just as a Jem'hadar soldier slams a rifle into his face.
- Serious Business: Jadzia decides to borrow Worf's favorite operas before he leaves and threatens to lose them if he doesn't return quickly.
- Shout-Out: Kira Title Drops a Star Trek: The Original Series episode when she refers to Dukat's "private little war."
- So Proud of You: Tain, in what is apparently the second bit of paternal affection he's ever shown Garak, admits to being proud of the way Garak refused to quit while trying to ride an animal as a child, no matter how many times he fell off.
- Take That!: Garak has some strong opinions about a certain kind of tea.Garak: I'd like to get my hands on that fellow Earl Grey and tell him a thing or two about... tea leaves.
- Talk to the Fist: As they're boarded by the Jem'Hadar, Garak politely asks if they could point them in the direction of the wormhole. Their response is to hit him with their rifle butt.
- This Is Not a Drill: When DS9 receives Worf's warning about the approaching Dominion fleet.Sisko: Put the station on Yellow Alert. Make sure everyone knows this is not a drill.
- Troll: Garak convinces Worf that he wants to join Starfleet, partly to practice lying (as he says, it's like any other skill) and partly just to screw around with Worf.
- Villain Decay: Invoked after Dukat confronts Kira over Ziyal's relationship with Garak.Dukat: Save your excuses, Major. You've betrayed me, and I promise you I won't forget it.
Kira: If that is a threat, I'm not impressed.
Dukat: There was a time when Bajorans took Cardassian threats seriously.
Kira: Not anymore.
- "Well Done, Son!" Guy: Garak laments that after spending his entire life trying to please Tain and allowing his father to mold him into a mirror image of himself, Tain remains cold, distant, and disappointed in him, even refusing, until literally minutes away from his death, to even acknowledge that Garak is his son at all.
- Wham Episode: The Dominion invades the Alpha Quadrant, Garak and Worf are taken prisoner, and Bashir is revealed to have been replaced with a Changeling spy who sabotages the crew's last chance to prevent the Dominion invasion.
- Wham Line: Moments before his death, the truth about Tain and Garak comes out.Garak: I'll do as you ask, on one condition...That you don't ask me this favor as a mentor, or a superior officer... but as a father asking his son.
- Martok's very first lines to Worf: "Do I know you?". While it had been implied back during "Apocalypse Rising", this (and Martok's subsequent exposition) explicitly confirms that Martok's first appearance back in "The Way of the Warrior" was actually the Martok Changeling rather than the genuine article. This is thus the very first time the characters and audience alike are meeting the real Martok.
- Wham Shot: Bashir being hauled into the prison barracks. Revealing there's a Changeling spy on the station. Also, note that Bashir is hauled in still wearing his old uniform. The spy has been on the station at least as far back as "Rapture"!
- The sight of a Dominion armada emerging from the wormhole. The invasion has begun.
- You Talk Too Much!:Ika'tika: (to Garak) You Cardassians are all alike. You talk too much.