It's pissed off Kira time. In this instance, she's fuming that a crew of Valerians have been permitted to dock at the station. Back during the occupation, the Valerians worked with Cardassia, supplying them weapons grade Dolamide. And she's convinced they're doing it again.
Sisko tells her that without proof, she can't do anything about it. Before it goes any further, their attention turns to a Klingon ship returning through the wormhole. A month ahead of schedule. And it promptly explodes.
O'Brien manages to beam one Klingon, Hon'Tihl aboard. But he can't be saved. He speaks one word before he dies: "Victory."
Hon'Tihl's ship was on a simple bio-survey mission. Which makes the weapons burns on his body and his cry of "Victory" rather unusual. Needing to get to the bottom of things, Dax and O'Brien head off in search of the ships mission recorder.
Odo drops by Quarks for his usual round of blackmail-assisted
info gathering. Quark mentions the crew, who trashed several holo-suite rooms by the way, spoke of something that would "make the enemies of the Klingon Empire tremble." That's all he has.
As Odo leaves, he's racked by a mysterious force. His head splitting in two, and Quark hurrying off to find Bashir.
Awakening in sickbay, Odo appears no worse for wear. Which is good, because Bashir has zero clue about how his body works. He prepares to leave, only to be stopped by Bashir. Who starts talking like a bad guy, and questioning him about an "Uneasy alliance" aboard DS9.
Bashir isn't the only one acting funny. Dax has gone spacey, randomly recounting old stories out of the blue. Kira has become a vicious conniver, looking to topple Sisko and O'Brien. Sisko has become an aloof and paranoid man, with O'Brien as his threatening right hand man.
With the mission recorder recovered, O'Brien sets to work decrypting the journal logs, while Sisko cowers in his room building a clock.
Odo is finally forced into action when Quark comes shuffling into his office, stuck in a neck-brace. While tending the bar, he overheard Kira trying to sway Dax onto her side in an attempted coup. Prompting Kira to threaten him into silence, and toss him like a ragdoll.
Examining the logs, Odo finds out the Klingon ship was destroyed from within. The crew was possessed by an extinct race known as the Saltah'na when they stumbled upon their mysterious energy spheres. The Saltah'na wound up destroying themselves in an internal conflict. And they've picked up right where they've left off in new bodies.
Working with Bashir to find a solution, Kira makes her coup attempt. It fails, and Sisko and O'Brien try beaming onto the Valerian ship. It's a no-go, and they only get transported into a corridor.
Odo is playing both sides of the conflict, herding all the possessed people into a cargo bay. With a specially designed program, he expels the Saltah'na from the crew, and jettisons it out the nearest airlock.
With that, things resume as normal aboard the station and Sisko finishes his clock, placing it as a permanent fixture in his office.
- Attention Deficit... Ooh, Shiny!: Dax under the influence of the Saltah'na. Also Sisko, to a lesser degree.
- Badass Boast
EVIL!SISKO: You know what disturbs me? The ingratitude. I offered you my kindness, my help, my leadership, and how do you repay me? With betrayal. But you won't get rid of me so easily. You see, unlike you, I understand history. My name will blaze across the stars long after your petty treacheries have been forgotten.
- The Caligula: Implied in Evil!Sisko's persona, who Mood Whiplashes between indifference to matters of state, to sudden outbursts of violence and Large Ham.
- Casual Kink: Odo is discussing the Klingons with Quark, who says, "Spare me from beings who think pain is pleasure. [beat] In small doses, perhaps..."
- Conflict Ball: In-Universe
- Conveniently Timed Attack From Behind: On several occasions someone is nearly murdered, but is saved by the intervention of a third party.
- Cut Comm Channels: Odo tries to let higher authority know what's going on, only to find the Subspace Ansible to Starfleet has been shut down under Kira's authority, while communications with the Bajoran Provisional Government have been cut off under O'Brien's authority.
- The Ditz: Evil!Dax, who appears to be channeling the persona of a senile old man, easily dominated by the forceful Evil!Kira.
- Double Entendre: Odo's first sign that the senior staff are acting strangely is when Bashir and Kira start smirking and talking in political double-speak.
- Dragon-in-Chief: Evil!O'Brien, who runs the station while Evil!Sisko is locked up in his quarters, working on his hobby.
- Dramatic Drop: Evil!Kira says that she's going to remove Sisko "one way or another". Cue Off Screen Crash as Quark drops a tray, tipping off Kira that he's listening in on their conversation.
- Easily Forgiven: Kira's attempted mutiny, since she wasn't herself at the time.
- Evil Is Hammy: Evil!Sisko is probably the worst offender.
- Evil!Bashir shows a lot of interest in political conspiracies. Five years later, Bashir gets recruited into Section 31.
- Evil!Kira has a seductive persona we're going to be very familiar with after meeting the Mirror Universe Intendant.
- Evil!O'Brien's plan for dealing with the mutiny involves fleeing Deep Space Nine and returning in superior numbers with a Federation attack force. This is what happens in Season Six.
- Guile Hero: Once Odo works out what's going on, he uses everyone's ambition and paranoia to get them into one place where the virus can be purged from their heads.
- He's Dead, Jim: Bashir re Hon'Tihl.
- Ice-Cream Koan
How are you, Lieutenant? EVIL!DAX:
You know what they say, put the shoe on the right foot first, but put the left foot first into the bathtub. EVIL!KIRA:
] I understand.
- Implausible Deniability: Odo suggests that the Ops staff may have been infected with a telepathic virus. Evil!Bashir acknowledges the possibility, but says it's unlikely as HE certainly isn't acting any different.
- Indirect Kiss: Evil!Kira drinks from Evil!Dax's Modela aperitif.
- Last-Second Word Swap: Evil!Bashir is handing an injector filled with poison to one of Kira's men, to be used in Sisko's assassination.
"It'll take effect in two minutes. Plenty of time to get a good— (Odo enters) Plenty of time for you to get a good night's sleep."
- Les Yay: Evil!Kira trying to win Dax over.
- MacGuffin: The Valerians only exist as the Conflict Ball between Sisko and Kira, never reappearing in the series.
- The Mutiny: Though those concerned are reenacting The Coup and act accordingly.
- Not Himself
- Somebody Else's Problem: Evil!Sisko ignores a brewing mutiny to construct and build a clock.
- Only Sane Man: Odo is the only one in Ops not affected by the Saltah'na.
- Out-of-Character Alert: And it only takes Quark getting assaulted for Odo to finally acknowledge it.
- "The Reason You Suck" Speech: Evil!Sisko gives one to Evil!Kira about her ingratitude.
- Rebel Relaxation: Odo enters his office to find Evil!Kira sitting in his chair, with her boots up on his desk.
- The Starscream: Evil!Kira
- Suddenly Shouting / Big "NEVER!"
What can we do? O'BRIEN: Leave the station
. SISKO: (jumping to his feet)
NEVER! GET ME A PHASER; I'LL GET RID OF KIRA!
- Thrown Out the Airlock: Once Techno Babble is used to force the telepathic virus out of everyone, Odo tells them to hold on and briefly opens the cargo bay door to space, where it disperses.
- Vitriolic Best Buds: When Odo collapses right after blackmailing Quark into providing information, the Ferengi rushes off shouting for Dr Bashir.
- What Happened to the Mouse?: We never find out what became of the Valerians, or what Sisko told them about what happened on the station.
- Wild Card: Evil!Bashir eagerly observes the impending crisis on the station, waiting to throw in his lot with whoever looks like winning.
- With Us or Against Us
O'BRIEN: Anyone who is against Sisko is against me.
- Would Hit a Girl: Evil!O'Brien cuffs Dax when she tries to signal Kira.