The Assignment (episode)
After returning from the Fire Caves on Bajor, Keiko's body is controlled by an alien lifeform that forces her husband O'Brien to do its bidding or else face the death of his wife.

Summary

Teaser
In Quark's, the day has started and Quark is busy. Rom enters, just off the night shift. Quark makes him his usual, puree of beetle, but Rom says today he'd rather try bacon and eggs with corned beef hash, a favorite of O'Brien's. Quark disapproves of the Human choice of dinner but begrudgingly makes it. As he normally does, he further questions Rom's choice of job, but Rom likes his job, despite being assigned to the graveyard shift fixing the waste extraction system.

Meanwhile, Miles O'Brien has discovered that Julian Bashir has accidentally killed Keiko's Idran hybrid bonsai trees that O'Brien was caring for while she was away visiting the Fire Caves on Bajor for the last five days. Bashir had dropped by the O'Brien's quarters and saw that the plants were dry, so he watered them. Unfortunately, too much water rots the roots. Upon spotting the ruined trees, Miles and Keiko's daughter Molly informs her father that "Mommy's going to be mad." Later, he welcomes Keiko home and immediately begins apologizing. However, as soon as she gets off the transport, Keiko informs Miles that she's not Keiko, but someone who has taken over her body. Whoever is inhabiting Keiko threatens Miles with his beloved wife's life and the life of their innocent daughter Molly claiming that they'll kill them both if he doesn't do exactly what she wants. O'Brien at first thinks that his wife is trying to play a joke on him, but is quickly persuaded otherwise when the entity causes her to choke. It stops choking Keiko just as easily to warn O'Brien off from calling the infirmary through his combadge.

Act One
Miles is ordered to reconfigure certain parts of the space station but is not told to what end. The alien convinces him that she can use Keiko's knowledge to know that Miles has already come up with a plan and will try to talk to the crew, however, it also assures him it will kill Keiko instantly, even if those plans have some success. They go back to their quarters, and Miles gets some more details. The alien is also determined to keep up appearances with their friends, answering the door when Bashir comes in, and promising to hold a birthday celebration for Miles, as Keiko had planned earlier before leaving for Bajor.

Soon, Rom is excited about being called to a meeting on the "swing-shift" to replace Duarte, an ill worker. He tries to fit in by asking what they drink on the shift, and asking where the ill worker normally sits, but the other workers treat him coldly. Unphased, he goes to the replicator and gets a raktajino. Just then, O'Brien appears on the monitor and assigns the engineers their jobs for the day, a change of plans. He gives a short description of what he's doing, and says he'll be working alone, asking them not to bother him unless it's absolutely necessary. 

As O'Brien works, he has the computer scan Keiko to confirm her identity, which it does. He then asks the computer how long it would take to knock out Keiko through various means; however, all would take too long as the entity only needs a fraction of a second to kill her. "God help me," O'Brien says as he then gets to work.

Act Two
During Miles' birthday celebrations, the inhabitant draws on Keiko's memories to flawlessly act like Keiko, and no one other than Miles knows any different. Captain Sisko is especially impressed by the Q'parol that she served, showing that the alien has access to all of her memories and talents. Jake Sisko asks Keiko if she saw any Pah-wraiths while in the Fire Caves, prompted by Odo's sharing of Bajoran legends. The inhabited Keiko teases Odo for believing in "the wraiths," which Odo denies. O'Brien has trouble keeping pleasant, and finally breaks his glass when he sees the alien kneeling down with Molly. With everyone else disturbed, he leaves to the other room and the alien follows. O'Brien insists he's done everything it wanted, but the alien admits that was just a test – the real work is to come. That night, Miles insists the alien tell him what to get done, but the alien is making the rules. It refuses and makes O'Brien sleep in the bed, for fear Molly will have a nightmare and come in.

In the morning, the alien hands him a PADD with his instructions. Miles finally decides to warn Sisko about what is happening, but before he can get to Sisko, he hears Keiko call out his name and watches in horror as the inhabitant forces Keiko to throw herself over the railing on the upper level of the Promenade. She lands in front of the Bajoran temple while Miles runs over and looks over Keiko helplessly.

Act Three
Dr. Bashir treats her injuries in the infirmary while Sisko and Odo question O'Brien about the incident and about why he was on the Promenade. O'Brien evades the questions by telling them he was planning on having lunch at the replimat and insists to Bashir that he visit Keiko at her bed. The evil inhabitant gives Miles an ultimatum: complete the reconfigurations in thirteen hours or it'll kill Keiko and Molly. O'Brien agrees, and leaves, starting a countdown clock to stay aware of the deadline. The alien asks O'Brien to give it a kiss, which he reluctantly does while Bashir stands nearby.

As he starts to get to work later, Rom comes to the chief, having finished his work already. Miles is very impressed that Rom got his workload done so fast and gets an idea. He decides to enlist his help to get the modifications done, claiming it's a secret assignment that Sisko and the senior staff know all about (while also warning him not to mention it to them). With the help of Rom, Miles manages to complete most of the work, however, as he is working in Ops in the early morning,  Dax pulls him away, having discovered anomalies in the station's systems. She shows what she's seen to him, and he brushes it off as minor deviations, but Dax suspects sabotage and intends to alert security and wakes Sisko.

Act Four
In the wardroom, Sisko calls a meeting of O'Brien, Odo, and Dax to discuss the sabotage. They eliminate other factors, and lead to one of the maintenance crew. Desperate to throw the officers off his scent and needing a distraction, O'Brien leads Odo to Rom, still working in a junction. Odo takes him to a holding cell, and O'Brien shares a knowing glance with him as he goes. Miles stays to survey the "damage" and then continues it. 

During the interrogation, Rom refuses to tell Odo anything (even his name), instead calling for O'Brien. Odo calls him to the security office, and pressed for time, O'Brien is forced to override security measures for the holding cell Rom is in, so that no one can listen in. He also has the computer reconfigure gravitic sensors, intending to be back within ten minutes. O'Brien goes to see Rom, who is concerned about the intensity of the interrogation, but also assures O'Brien he will stick to their "mission." However, Rom then asks why O'Brien's modifications are converting the station into a gigantic chroniton emitter. O'Brien is surprised he guessed it. Rom believes the intent is to kill the wormhole aliens, and asks why they are doing that. O'Brien is stunned.

Act Five
O'Brien hadn't realized the effect of the chronitons on the wormhole aliens, having been so on edge. He wonders aloud about this, making a connection between the wormhole aliens and the Pah-wraiths. Rom, having been educated in Bajoran myths by Leeta, explains that according to the Koss'moran, the Pah-wraiths were cast out of the Celestial Temple by the Prophets. O'Brien now knows that Keiko's intruder can only be a Pah-wraith from the Fire Caves, and that it is planning to use a chroniton beam to kill the Prophets. O'Brien asks Rom to play dumb for awhile and rushes out.

He gets back to work on the junction, with a newfound purpose, however, the newly-solid Odo confronts him. He knows that O'Brien was behind the modifications, so O'Brien knocks him out. He finishes the station modifications, and takes the Keiko/Pah-wraith to a runabout, coldly telling it that he figured out its plan but doesn't care about the Prophet/Pah-wraith conflict: he only wants his wife back. Once in position near the wormhole, O'Brien activates the emitters on the station, but as the Pah-wraith eagerly anticipates the death of the Prophets, he targets the runabout instead of the wormhole, the deranged Pah-wraith screaming in pain as it dies. Keiko and Miles embrace. When they return, Sisko asks Miles for an explanation.

Back in their quarters, Keiko reveals that she was conscious the entire time, but the Pah-wraith was in complete control of her body. Her mind was a helpless observer, "like being stuck in sand and squeezed" whenever she tried to move, hearing and feeling herself speak and unable to affect any of it. She was, however, able to feel its emotions sometimes, but there was only a cold rage. Keiko tells Miles that she doubts the Pah-wraith would have spared either of them.

The next day, a tired but excited Rom enters Quark's. Quark warns him that the night shift is obviously too much for him, but Rom explains that he wasn't working, rather he was out celebrating his now permanent promotion to the day shift; his reward for helping O'Brien. Quark sighs as Rom then proceeds to order pancakes, sausages, and pineapple: the breakfast of the day shift.

Memorable quotes
"Is there something wrong, Chief? I can work slower if you want me to."
 - Rom

"Culpable deniability. I understand. Don't worry about me, Chief. My lips are sealed. Nobody will get anything out of me. Not even my name."
"Rom, everybody on the station knows your name."
(confused) "Right." (a pause) "But I won't confirm it."
 - Rom and O'Brien

"Everyone has enemies. Even the Prophets."
"That's right. They're not just wormhole aliens; they're Prophets. Part of Bajoran mythology, just like the Pah-wraiths of the Fire Caves. So what have those wraiths have to do with the wormhole aliens?"
"Kosst Amojan."
"What?"
"It's a Bajoran legend. From the verb Kosst, meaning 'to be', and Amojan, 'banished'. Leeta's been telling me all about Bajoran legends. She can go on for hours. She says I'm a good listener."
 - Rom and Miles O'Brien, about the Pah-wraiths

"According to Leeta, the Pah-wraiths used to live in the wormhole. They were part of the Celestial Temple."
"They were Prophets?!"
"False Prophets. They were cast out of the Temple, exiled to the caves where they were imprisoned in crystal fire cages and forbidden to ever return lest they face the wrath of the true Prophets."
"So if these false Prophets were to return to the Celestial Temple…"
"I don't think they'd be welcomed."
 - Rom and Miles O'Brien, about how the Pah-wraiths were banished from the Celestial Temple by the Prophets

"For the first forty minutes, it was like pulling teeth even getting him to admit his name."
 - Odo, after interrogating Rom

"Well, Rom, I'm glad things are going so well for you."
"No, you're not. But thanks, anyway, brother."
 - Quark and Rom

Background information

Story and script
 In Robert Lederman and David R. Long's original version of this story, Keiko O'Brien is on a biological expedition to a planet inhabited by non-corporeal beings. When she returns to the station, one of the beings accompanies her, and has her under its control as a hostage. René Echevarria changed the premise of the story to be more focused on the possession aspect than that of the hostage situation. ()
 After Ira Steven Behr assigned David Weddle and Bradley Thompson to compose the teleplay for this episode, they were unsure as to what direction to take it in until Hans Beimler pointed out to them that this was another 'O'Brien must suffer' episode. Beimler also summed up the tone of the show as "everyone comes over for a party when you're having a huge fight with your wife and she acts as if everything is perfectly normal." After talking with Beimler, Weddle and Thompson had no problems writing the teleplay. ()
 This episode was also the first produced teleplay for David Weddle and Bradley Thompson, who had pitched the story for the fourth season episode . Furthermore, this episode is also the first episode with music by Gregory Smith.
 This was the first episode to mention the Pah-wraiths, the demons of Bajoran religion who are the enemies of the Prophets. O'Brien mentions the Fire Caves, where Kai Winn later attempts to summon the Pah Wraiths in . However, although this episode represents the first time the Pah-wraiths are mentioned, the origin of the concept can actually be dated back to the first season episode . While developing "The Assignment", René Echevarria was trying to come up with a concept that would tie into the  mythology. He didn't want the being who possesses Keiko to simply be some random entity, but rather something that would fit into the overall scheme of the show. Ultimately, he suggested that perhaps the aliens in the wormhole weren't all good, and that there were in fact some evil members of the race. Echevarria, however, had no idea that four years previously, Robert Hewitt Wolfe had come up with exactly the same idea. In the episode , Sisko and Jake are supposed to visit the "Fire Caverns" on Bajor, and there was a line in the original teleplay where Sisko is told jokingly to "watch out for the Pagh-wraiths." The Pagh-wraiths were Wolfe's idea and were supposedly little goblin creatures that lived in the Fire Caves, having been cast out of the wormhole and given corporeal form. It was only when Echevarria was trying to find some connection between "The Assignment" and previous episodes that Wolfe returned to his old Pagh-wraiths concept. () Of course the Pah-wraiths went on to play a huge role in future Deep Space Nine storylines, especially towards the end of the seventh season.
 According to Wolfe, the common spelling of Pah-wraiths is actually a misspelling, and his original 'Pagh-wraiths' is the correct form; however, David Weddle disagrees, arguing that 'Pah' is correct if the term comes "from ancient Bajoran. The g's were added centuries later, when the seventh hemisphere became more influential." ()
 In this episode, Rom tells O'Brien of the myth of the Koss'moran, which comes from the Bajoran verb "kosst," meaning "to be," and "amoran," meaning "banished." According to the , Koss'moran is the same thing as Kosst Amojan – they both mean "to be banished". The phrase Kosst Amojan appeared in the episode , but it was not revealed as meaning anything specific. Although most fans seem to assume that Koss'moran and Kosst Amojan are actually two different concepts, according to the Companion, they represent exactly the same idea. René Echevarria simply altered the name because he didn't like the sound of Koss'moran.
 Nana Visitor (Kira Nerys) does not appear in this episode because she went into early labor during production. This is the first episode of the series in which she does not appear. Originally, the party in the O'Brien's was going to be a Bajoran holiday presided over by Kira, but when producers discovered she was unavailable, they did a quick rewrite of the scene and turned it into a birthday party, while also ensuring to explain Kira's absence. ()

Reception
 Colm Meaney enjoyed the episode. He commented: "That was great. Roz's performance in that, I thought, was spectacular. It was the first time she really had an opportunity to do her thing. You got to see her range in way you hadn't before, playing Keiko and the alien horror. From my end of it, it was good writing, good drama. It was a solid idea to have Miles do something against his will, to have him be coerced. It was a good episode, very strong". ()

Trivia
 This was Allan Kroeker's first Star Trek directing job. Kroeker would go on to direct almost forty episodes across DS9,  and  including the finales of the fifth, sixth and seventh seasons of DS9, the finales of the sixth and seventh seasons of Voyager, and the finales of all four seasons of Enterprise.
 This episode went into production after , but it aired the week before, presumably due to the lengthy post-production on "Trials and Tribble-ations".
 During the party, Jake Sisko says that he has always wanted to meet a Pah-wraith. A year later he is possessed by one in .
 Keiko's possession by a Pah-wraith differs from later episodes. When Jake and Dukat are later possessed by Pah-wraiths their eyes glow red and their voices take on a metallic, echoing effect. Neither of these physiological changes occur to Keiko. It may be possible the Pah-wraith deliberately concealed this, as such changes would've undoubtedly garnered unwanted attention.
 Since O'Brien's birthday was revealed to be in September in , this episode is set in September 2373.
 This episode features an alien officer called Abdon, who bears a strong resemblance to a Kobali. However, the two make-ups are not identical.
 Five years earlier, Miles O'Brien was possessed by an alien consciousness in a similar way to his wife Keiko in this episode. ()
 After Keiko's fall on the Promenade, Bashir diagnoses her with a "hairline fracture of the right parietal lobe," which is actually part of the brain. The scripted line was bone.
 This was the first of three episodes of the show to be scored by Gregory Smith, who usually worked as the orchestrator for frequent Star Trek composer Jay Chattaway.

Remastered version
Remastered footage from the episode is featured in the documentary What We Left Behind.

Video and DVD releases
UK VHS release (two-episode tapes, CIC Video): Volume 5.3, 
As part of the 35 Jahre Star Trek German VHS release
As part of the DS9 Season 5 DVD collection

Links and references

Starring 
 Avery Brooks as Captain Sisko

Also starring 
 Rene Auberjonois as Odo
 Michael Dorn as Lt. Commander Worf
 Terry Farrell as Lt. Commander Dax
 Cirroc Lofton as Jake Sisko
 Colm Meaney as Chief O'Brien
 Armin Shimerman as Quark
 Alexander Siddig as Doctor Bashir

Guest stars
 Rosalind Chao as Keiko O'Brien / Pah-wraith
 Max Grodénchik as Rom
 Hana Hatae as Molly O'Brien

Co-stars
 Patrick B. Egan as Jiyar
 Rosie Malek-Yonan as Tekoa
 Judi Durand as Cardassian Computer Voice
 Majel Barrett as Federation Computer Voice

Uncredited co-stars 
 Bill Blair as Yridian visitor
 Byrne as Bajoran Ops crew
 Uriah Carr as operations officer
 Brian Demonbreun as civilian
 Kathleen Demor as operations officer
 Steve Diamond as Bajoran civilian
 Dorothy Hack as Bajoran woman
 Jasmine Gagnier as operations officer
 Terry Green as operations lieutenant
 Wade Kelley as operations officer
 Mary Mascari as Bajoran woman
 Robin Morselli as Bajoran command officer
 Bill Thomas Miller as command officer
 Chuck Shanks as operations lieutenant
 Mark Allen Shepherd as Morn
 James Lee Stanley as Bajoran security deputy
 William Steinfeldt as Bajoran ops officer
 Unknown performers as
 Abdon
 Alien with head tentacles
 Bajoran deputy

Stunt doubles 
 Jennifer Caputo as stunt double for Rosalind Chao
 Dennis Madalone as stunt double for Colm Meaney

Stand-ins 
 John Lendale Bennett
 Uriah Carr
 Cathy DeBuono 
 Mark Lentry
 James Minor
 Robin Morselli
 Randy Pflug
 William Smith for Max Grodenchik
 Brenda Jean Wright

References
anesthetine gas; bacon; Bajor; Bajoran; Bajoran language; Bajoran mythology; Bajoran spiny basil; Bajoran wormhole; bar; bed; birthday; birthday cake; blood vessel; "bloody"; bonsai tree; brain; brain hemorrhage; breakfast; butter; Cardassians; Cardassian vole; cascade feeder; Celestial Temple; "Chief's Special"; chocolate; chroniton beam; coffee; com-link; corned beef hash; couch; crystal fire cage; culpable deniability; dabo girl; Dahkur Province; data banks; Davis family; day shift; Deep Space 9 levels; deflector grid; Delavian chocolate; dermal regenerator; Diagnostic and Repair Technician, Junior Grade; Duarte; eavesdropping device; eggs; EJ7 interlock; emotion; exile; eyebrow; fashion; femur; Ferengi; fiber optic relay; Fire Caves; flow regulator; "For He's a Jolly Good Fellow"; frequency; fungi; God; gravitic sensor; hairbrush; hairline fracture; haunted; heart; hostage; iceberg; Idran hybrid; imaginary patient; impulse thruster; Irish whiskey; inertial coupling port; isolinear chip junction; isolinear rod; Joow; junior engineering chief; kiss; Koss'moran; laser torch; Leeta; ; level 3 diagnostic; level 3 stasis field; listener; Litana; lunch; Lupi; magnetic constrictor; maintenance technician; night shift; nightmare; nosebleed; operating table; optronic integrator; orange juice; pah-wraith; pancakes; parietal lobe; ; phase shift; phaser; physical intimacy; pineapple; polarity; Promenade; Prophets; puree of beetle; purple; Q'parol; Quark's; radiometric anomaly; raktajino; repair log; Replimat; root; rot; Rudellian brain fever; runabout; sabotage; sausage; Shakaar Edon; shock; shoe; Starbase Sierra Tango; slug liver; staff meeting; stun setting; supernatural being; swing shift; Tellurian mint truffle; temporal disruption; verb; walkway; waste extraction system; water; wideband filter protocol; worker; wormhole alien; wrath; Yridian

External links 
 
 
 
 
 

de:Die Erpressung
es:The Assignment
fr:The Assignment (épisode)
nl:The Assignment
Assignment, The