Invasive Procedures (episode)
A desperate Trill tries to steal the Dax symbiont.

Summary

Teaser 
"Station log, Stardate 47182.1. DS9 has been temporarily evacuated due to a violent plasma disruption. Until the disturbance ends, we'll be forced to maintain the station with a skeleton crew."

The crew of Deep Space 9 evacuates to avoid an impending plasma storm, leaving a skeleton crew. Jadzia Dax has the  ready at Landing Pad C in case of emergencies. Miles O'Brien and Odo are checking the station and are at the docking ring. A loud banging reveals Quark hiding in one of the airlocks. He goes back to his bar, but they don't see a device on the wall beeping as they leave.

Act One 
While monitoring the storm and securing the station, the crew receives a distress call claiming to be from a cargo ship called Ekina. O'Brien and Odo go down to meet them, but the crew is hostile. A timid Trill named Verad and his crew (a pair of Klingon mercenaries, T'Kar and Yeto, and former prostitute Mareel) surprise them. T'Kar directs the takeover, forcing Odo into a locked box, and capturing O'Brien and Dr. Bashir, but not before forcing Bashir to put the box in stasis in the infirmary. The group then goes to Ops and captures the rest of the crew. In the corner, O'Brien realizes Quark probably had a hand in them getting around the security measures and notes this to Sisko.

Yeto goes to Quark's bar and makes it clear he is not going according to the plan Quark understood (a business transaction), and brings him to Ops under guard. There, Verad, again timidly, states he wants the  symbiont.

Act Two 
Verad explains he is bitter because he applied to be "joined" and was rejected after a lifetime of preparation and sacrifice when the Symbiosis Evaluation Board declared him unsuitable for joining. He targeted the Dax symbiont specifically, as it is the most compatible for him, and furthermore plans to escape to the Gamma Quadrant to start a new life. Bashir attempts to refuse to perform the procedure, but Verad shoots O'Brien at his right shoulder, making it clear he will hurt everyone there if he does not get what he wants. He allows Bashir to tend to O'Brien briefly, and Jadzia submits in order to prevent further harm, even though she knows removing the symbiont will kill her within a few hours. Yeto then escorts them to the infirmary, leaving Mareel and T'Kar. 

Verad forces Bashir to transfer the symbiont into his body while he's awake, using a neuro-electrical suppressor, and demands a monitor to watch the procedure. Bashir reluctantly puts Jadzia to sleep, asking for forgiveness. Yeto watches as Bashir performs the operation successfully, asking forgiveness from Jadzia.

In Ops, the crew waits and has a quiet conversation. Demanding silence, T'Kar starts a scuffle and O'Brien is attacked. Mareel subdues Kira and gets the upper hand with a phaser. Later, Kira gets Mareel to talk. She informs them she knew Verad a long time ago back when he was a communications clerk at the Federation Consulate on Khefka IV and he helped her out of a bad situation, and that she loves him. She doesn't believe Sisko's point that a joined Trill becomes an entirely different person than before, and that she will lose him.

At that point, Verad Dax appears, completely calm and confident.

Act Three 
Bashir has Yeto act as a nurse as he tries to save Jadzia's life. Yeto resists, trying to get a rise out of Bashir, but does eventually help him. She wakes up feeling very alone. He promises to save her, and tells her to rest.

Meanwhile, Sisko tries to coax his old friend (Verad now has the memories of both Jadzia and Curzon Dax) into setting things right, first by recalling memories going back to when they first met at Pelios Station, but eventually mentioning discovering the Bajoran wormhole, one of Jadzia's memories. This gives him pause, but he says it's too late, that the integration is already happening and the symbiont is too weak to undergo the procedure again. He then justifies it by saying he wants to benefit many worlds in the Gamma Quadrant with his knowledge and experience, including Jadzia's memories. Mareel questions why Verad is entertaining the conversation at all and gets a snap retort from Verad – she begins to realize how much he has changed, but continues to remain loyal to him. 

Sisko realizes Verad intends to let Jadzia die, and ends their friendship abruptly. This affects Verad.

Act Four 
Verad's group waits the storm for safe passage to the wormhole. Meanwhile, Mareel attempts to give O'Brien a Senarian egg broth to help him with his strength, which he reluctantly accepts. Mareel looks up to Verad, who is thinking alone in Sisko's office, and Sisko again tries to convince her he's changed more than she realizes. She stays loyal, but the talk gets heated. Seeing this, Verad comes out from Sisko's office, but she assures him everything is fine. Just then, Quark attacks T'Kar, and pretends to be injured so he is taken to the infirmary. Verad orders Mareel to take him down. There, Quark squeals and signals to Bashir to "run some further tests." Mareel leaves Yeto alone with him and Bashir, giving the two their opportunity. Bashir knocks him out with a hypospray, then removes the container Odo is in from the medical bay's stasis field. Bashir does not see how the container can be opened without the access code, but Quark identifies its Delgorian locking mechanism, which he manages to crack using his superior hearing and a bit of impromptu "surgery" with one of Bashir's laser scalpels.

Mareel goes to Verad and they plan their escape. Verad wants to ensure she is safe, however, when Mareel mentions them being together, he is reluctant to reciprocate. Now, Mareel is doubtful.

Once Verad realizes Yeto is subdued, he guesses that Odo is free and immediately heads for his ship with T'Kar. He takes Kira as a hostage just in case. Mareel wishes him luck, staying behind in Ops. Verad bids Sisko farewell, wishing they could stay friends, but Sisko promises him they'll be seeing each other again. This stuns Verad a bit, but he leaves.

Act Five 
Sisko goes to Mareel again, asking about the rendezvous since he knows it will never happen. She's now convinced Verad lied to her about the rendezvous, which he has never done, and finally accepts that the "new" Verad is no longer the man she loves.  Sisko promises that he will save both Verad and Jadzia by removing the symbiont from one and replacing it in the other. Mareel relents and surrenders her phaser and combadge, but promises to kill Sisko if Verad is not brought back alive. He believes her.

By the time Verad reaches his ship, Odo has released the docking clamps, leaving him stranded. Verad runs when he sees Odo, leaving T'Kar to be overpowered by both Odo and Kira. Verad heads for a different runabout in a neighboring airlock, but runs into Sisko and the two have a stand off. Believing that Sisko will not shoot his old friend in fear of harming the symbiont, Verad begins to walk away, but Sisko shoots him with his phaser anyway, declaring, "Don't call me Benjamin." 

Fortunately, Bashir successfully reverses the symbiont's host, and Verad wakes up without it. He is very shaken up, despite Mareel's devotion and her promise that she will never leave his side. Meanwhile, Jadzia wakes up on the next table and gratefully embraces Sisko. She confides that the symbiont's brief contact with Verad has given her his memories - "and it's all so sad". Even though the procedure has been reversed, Verad is now part of the Dax symbiont forever.

Log entries 
 Station log, Deep Space 9, 2370

Memorable quotes 
"He couldn’t find a cup of water if you dropped him in a lake but, even if he is an idiot, he’s still my brother."
 - Quark

"I’ve struck the sails and battened the hatches, so to speak."
 - Bashir

"The Empire is governed by doddering fools and frightened old women who aren’t worthy of the name “Klingon.”"
 - T'Kar

"It’s such a pleasure doing business with Klingons."
 - Quark

"Either you help me, or you and your friends will die."
 - Verad to Bashir

"Thank you, Doctor. I feel better already."
 - Quark, after Bashir sedates Yeto

"It's a gift."
 - Quark, after unlocking Odo's container

"She let herself be slaughtered like a mindless t’gla. If she wanted to live, she should have fought back."
 - Yeto, to Bashir

"Don't call me Benjamin."
 - Sisko, to Verad

Background information

Story and script
 Robert Hewitt Wolfe says that this show was created because the producers wanted to convey to the audience the idea that not every single Trill was joined, that it was actually extremely difficult to get a symbiont. This, in turn, offered a commentary on the Jadzia character insofar as she was someone who did become joined. (Star Trek: Deep Space Nine Companion)

Production
 The symbiont seen in this episode is significantly different from that seen in . As makeup supervisor Michael Westmore explains, the original design was based upon a caterpillar with an octopus' head, but for its second appearance in DS9 (the first was in the pilot ), the design was "streamlined." (Michael Westmore's Aliens: Season Two, DS9 Season 2 DVD, Special Features) 
On the scene featuring the Trill symbiont, David Livingston commented, "We didn't want it to look cheesy. It was always a problem showing it. It's that whole idea of ; you don't really want to see it too much because the audience is either going to be repulsed by it or say it's too hokey. (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages)
During filming, Tim Russ accidentally punched Patricia Tallman (who was doubling Nana Visitor) in the face during a fight sequence. Tallman noted that "everyone on the set freaked out, but I said, 'No, don't stop! That was really good – it looked very authentic!' So we finished the fight there and then." (Star Trek Monthly issue 52)

Continuity
The third season episode  expands on the highly selective and exclusive process of joining. It is explained that if the widespread compatibility of most Trill with symbionts was known, violent attempts at joining such as Verad’s would be far more common.

Reception
Ira Steven Behr commented: "Glover was great, but so was Megan Gallagher. I thought she was just wonderful. It was one of my favorite shows of the season. I love the stuff with Verad becoming Dax and the scene with him and Sisko where he's suddenly his friend. It was very interesting material and well played. Les Landau did a wonderful job with that show". (The Deep Space Log Book: A Second Season Companion, p 21)
Robert Hewitt Wolfe commented: "I'm really pleased with "Invasive Procedures". John Glover as Verad turned in a tour de force performance. Avery, as usual, was great. Les Landau gave it excellent direction. It was neat to do this kind of film noir study of our characters. It was especially good for Bashir, who shows he's not only a competent doctor, but he's tough, too. He stands up to the Klingon, then, later. The episode showed a part of Bashir that we hadn't seen before". ("Robert Hewitt Wolfe – writer/story editor", )
Michael Piller commented: "I've been extremely pleased with the growth of Terry's performance. I thought she was very touching in this episode, and the ensemble really worked together very well. John Glover was terrific. We basically took our cue from shows like  and ." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages)
This is one of Terry Farrell's favorite episodes because she believes it is very important in terms of differentiating between the host (Jadzia) and the symbiont (Dax); "I approached the scenes in the Infirmary with the idea that Jadzia is scared, that she feels helpless. She cares very deeply for everyone on the station and is afraid for them. That's why she's willing to say 'Fine, I'll give my life for everybody, and you can have Dax.' But that had been while the strength of Dax was inside of her, telling her that everything was going to be okay. Once the worm is gone, she's only twenty-eight years old, and it's like, 'Wait, I haven't lived that much life yet'." ()
When asked after leaving Star Trek: Deep Space Nine who her favorite guest was, Terry Farrell commented "John Glover, absolutely. He was Verad in "Invasive Procedures", the guy who stole my Dax symbiont. He's such a great actor and I was so psyched that he did our show. He said somewhere that he liked working with me, and I was so excited and flattered to hear that". ("Farrell's Fate", Star Trek Monthly, issue 43)
Armin Shimerman dislikes this episode because he feels that Quark commits an unforgivable crime yet receives no punishment. According to Shimerman, "I worry when Quark doesn't get punished for really sizable crimes. It makes the character less important since his acts trigger no consequences, and it makes Odo look a little foolish, in that he's the law keeper and he can't get this little troll punished." ()
Megan Gallagher commented that "Invasive Procedures" had "a good back story. I loved working with John Glover. The whole cast was great. Nana (Visitor) and I had a cool fight scene to do. She has a theater background and I have a theater background. I’d studied stage fighting and combat and all of that. So that was fun, going into your tool box and using something you paid a lot of money to learn how to do". 

Trivia
 This is the second episode in a row after  wherein most of the crew is evacuated from the station, while Quark is left behind and Rom receives passage. 
Cirroc Lofton (Jake Sisko) does not appear in this episode.
Tim Russ makes his second Star Trek appearance in this episode. The first was in TNG's . His next appearance outside  was as a Lieutenant aboard the  in . He returned to DS9 to play the mirror universe version of Tuvok in , the following year.
 Video and DVD releases 
UK VHS release (two-episode tapes, CIC Video): Volume 12, .
As part of the DS9 Season 2 DVD collection.

 Links and references 

 Guest Stars 
 John Glover as Verad
 Megan Gallagher as Mareel
 Tim Russ as T'Kar
 Steve Rankin as Yeto

 Stunt doubles 
 George Colucci as stunt double for Armin Shimerman
 Irving Lewis as stunt double for Tim Russ
 Patricia Tallman as stunt double for Nana Visitor
 Spice Williams as stunt double for Megan Gallagher
 Unknown stunt performer as stunt double for Colm Meaney

 References 
airlock; Andorian redbat; Anastasia; auricular lobe; bachelor party; Bajoran wormhole; ; body; brother; bulkhead; buyer; Cardassians; Cliffs of Bole; communications clerk; consulate; contusion; crystallization; cup; ; ; ; ; Deep Space 9 levels; Delgorian locking mechanism; delta-wave inducer; docking pylon; docking ring; dozen; Ekina''; endorphin; evacuation shuttle; Federation; Ferengi; Gamma Quadrant; gold-pressed latinum (latinum); healing; heart; Kela; Khefka IV; Klingons; Klingon Empire; Klingonese; Kustanovich; lake; liquid data chain; ; malleus; military mastermind; neuroelectrical suppressor; operation; ; Pelios Station; plasma discharge; plasma disruption; plasma storm; prisoner; Promenade; Quark's; rebirth; Rom; runabout; runabout pad; safe passage; science officer; second; security grid; Senarian egg broth; "shifter"; shuttle; skeleton crew; slip of the tongue; spitting; Starfleet; stasis chamber; Symbiosis Evaluation Board; tractor beam; Trill;  (planet); Trill symbiont; water; wedding

External links
 
 
 
 

de:Der Symbiont
es:Invasive Procedures
fr:Invasive Procedures (épisode)
it:Il simbionte (episodio)
nl:Invasive Procedures
DS9 episodes