Arjin, a Trill seeking to become joined with a symbiont, has arrived on the station to be examined for two weeks by his field docent, Dax. Arjin is nervous to meet Dax because she (or rather her symbiont itself), is infamous for going hard on initiates. Bashir welcomes him to the station and introduces him to Dax, who is gambling with Ferengi. Arjin's first few interactions with Dax go smoothly enough. While displaying her confident, wise, and freewheeling lifestyle to the uptight Arjin, she assures him that ''Jadzia'' Dax is not the same person as Curzon Dax and won't go too hard on him.

However, the more Dax gets to know Arjin, the less impressive he seems. He's insecure, meek, and obsequious. When Dax takes him through the wormhole, he can't even react to its beauty without simply echoing Dax's own thoughts, which she notes. Dax is going easy on him, noting that Curzon was her own field docent before she became joined with his symbiont, and he flunked her, so she knows how traumatic that kind of approach can be. The one thing Arjin is good at is piloting, so Dax takes him on a trip through the wormhole. During the voyage, however, the pair's runabout picks up some sort of "space seaweed." Dax has it beamed to a lab and quarantined for study.

While this is going on, O'Brien and the rest of the staff are fighting off an infestation of Cardassian voles, which are eating through every system they come across and causing a variety of problems. When O'Brien calls Gul Evek to ask for help, the Cardassian simply laughs at him and says that Starfleet can hand the station back any time they please.

Over a game of chess with Sisko, Dax relates her doubts about Arjin's suitability. She doesn't want to confront him because then she would repeat the harsh approach of Curzon, but Sisko urges her to push him. While studying the anomaly, Dax finally begins to get critical of Arjin, accusing him of having no will of his own: He's only applying to be a host to satisfy his father's wish, he has no future plans that he can articulate if he should become a host, and he only tells Dax what he thinks she wants to hear. Arjin blows up at Dax and storms away to drown his sorrows at Quark's.

Left to her own devices, Dax discovers that the "seaweed" is actually a proto-universe. As it develops, it threatens to displace their own universe. The natural course of action is to destroy the proto-universe, but then Dax discovers signs of what might be life. Time might be passing at an accelerated rate within the proto-universe, so destroying it now could mean the mass murder of entire civilizations. Kira argues to destroy the proto-universe anyway, because it's "us or them," but Odo urges Sisko to find another way. Sisko announces he'll decide in an hour, the fate of two universes now in his hands.

After chatting with Jake about his new girlfriend, a dabo girl, Sisko thinks about the voles rampaging through the station, not caring about the destruction they cause. He decides not to act like a vole and orders the proto-universe to be taken back through the wormhole, hopefully to return it to where it came from. Dax finds Arjin and enlists his crack piloting. With a whole lot of {{technobabble}} support from the station, Dax and Arjin ditch the proto-universe and have to make it back without running into any verteron nodes. Arjin is unsure if such a feat is possible, but with Dax's moral support, he deftly flies them back to safety.

Bidding Arjin farewell, Dax tells him that this will look good on his host application. In the end, however, she tells him that she ''may'' someday recommend him to become a host... when he's ready. Once he leaves, Dax announces proudly to herself, "I'm not Curzon!"

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!!Tropes
* AcePilot: Arjin. A level 5 pilot to be precise, which comes in handy for flying through the wormhole without hitting any verteron nodes.
* ActualPacifist: Kira argues in favor of destroying the proto-universe by saying it's no different than stepping on ants. Odo replies that he ''doesn't'' step on ants.
* ActuallyPrettyFunny: When Quark tells O'Brien that Kira insists on fighting her latent attraction to him, O'Brien actually chuckles.
* AlienAnimals: Cardassian voles resemble very large, mostly hairless earth rats with six legs, spoon-bones on their heads, and a bunch of ridges. So cute!
* AndThenWhat: Jadzia has questions about what Arjin's personal ambitions are after he's joined. He doesn't really ''have'' any.
* BeYourself: Jadzia tells Arjin that he needs to focus on his own course in life rather than just do what his father or teachers expect of him.
* BittersweetEnding: Arjin makes good with his piloting, and he and Dax part on friendly terms, but he's still not ready to become host material. Dax very politely tells him that she's flunking him, saying only that she'll recommend him as a host in the future, when he's ready.
* DatingWhatDaddyHates: Well, "hates" might be a little strong, but Sisko isn't happy about Jake being in love with a dabo girl.
* DesperatelyLookingForAPurposeInLife: Jadzia notes that Arjin doesn't seem to have any ambitions or plans for the future--only vaguely noting that his options will open up if he's joined--and questions whether he even truly ''wants'' to be joined, especially in light of the fact that his father basically guilted him into entering the program. She tells him to figure out what he ''really'' wants.
* DontCallMeSir: Jadzia doesn't want Arjin to call her "Ma'am" or "Lieutenant", preferring FirstNameBasis.
* TheDreaded: No Trill initiate wants to be assigned Dax as a field docent because of the large number of candidates previous Dax hosts have rejected (especially Curzon, whom Jadzia has less-than-fond memories of).
* DrillSergeantNasty: Curzon Dax developed a reputation among Trill initiates for being one of these--quite a contrast from his usual personality.
* DrowningMySorrows: Arjin parks himself in Quark's bar, convinced that he's torpedoed any chance of getting a good recommendation.
* FirstNameBasis: Jadzia rejects Arjin calling her [[MaamShock "Ma'am"]] or "Lieutenant" in favor of this.
* FromBadToWorse: {{Implied}} re the voles -- apparently, their mating season is coming up.
* HypocriticalHumor: Sisko expresses disappointment that Jake was hiding a new relationship from him. He then freely admits to his son that he would not have been understanding if told the truth right away.
* IHatePastMe: Jadzia was on the receiving end of Curzon Dax's borderline-abusive training prior to becoming joined to the Dax symbiont herself and wants as little to do with that style of training as possible. She eventually realizes, however, that at least some amount of the ToughLove Curzon subjected her to is necessary to break candidates out of the rut they tend to naturally develop during their training.
* LossOfIdentity: Trill hosts without a strong enough personality can be overwhelmed and dominated by their symbionts. That's one reason why Arjin's wishy-washy attitude is a problem.
* MakeSomeNoise: O'Brien designs a sonic-based weapon to try and drive the voles out of the station. It proves to be good at deafening ''Quark'', at least.
* MsFanservice: Jadzia wearing only a ModestyTowel. Quark notes that the promenade is filled with people who pine after her, including himself.
* MySisterIsOffLimits: How Quark screwed up his chances of being more than a bartender.
--> "Rule of Acquisition 112: Never have sex with the boss's sister."
* NewMeat: Arjin's highly straitlaced and expects Jadzia to be the same, given Curzon's reputation.
* NotSoDifferentRemark: In his CaptainsLog, Sisko wonders if destroying the mini-universe would make him no different from the Borg.
* OpenMouthInsertFoot: When Sisko comes home early, Jake thinks O'Brien spilled the beans about his relationship, so he starts talking. After Sisko reacts with surprise over him dating a dabo girl, Jake realizes O'Brien didn't say anything as promised, so he has this reaction.
* ParentalFavoritism: Arjin's father favored his sister, whom he pushed into joining. However, partway into her training, she ran off and got married. On his deathbed, the old man told Arjin that he was his last hope.
* RaceAgainstTheClock: When the crisis heats up, Sisko reflects in his log that he has to make a very big decision in one hour.
* RenaissanceMan: Dax's early scenes establish her as one, thriving in a wide variety of environments and mastering many pursuits, while Arjin can only gape and fidget.
* SarcasmBlind: Quark, after telling a depressed Arjin his story about how he blew his own shot at success, which, of course, only makes the Trill feel even worse.
-->'''Quark''': You only get one shot at the latinum stairway. If you miss it, you miss it. Welcome to the club, son.\\
'''Arjin''': ...Thanks.\\
'''Quark''': Glad I could help.
* ShrinkingViolet: Pre-joining, Jadzia was like this.
* SternTeacher: Curzon was one of these, demanding the best from his students--in fact he actually recommended Jadzia be dropped from the program.
* ToughLove: While Dax characterizes Curzon's treatment of her as "borderline abusive," Sisko argues that confronting her on her shortcomings was necessary for her eventual success. Indeed, Jadzia's drive to exceed her own limitations was sparked after Curzon flunked her.
* TheUnfavorite: Arjin's sister, who disappointed their father by declining to be joined.
* WellDoneSonGuy: Arjin seems mostly in the Host Program because it's what his father wanted.
* WhatTheHellHero: When Kira suggests destroying the protouniverse before the next expansion, Odo expresses outright disgust with her and calls such a suggestion mass murder. Kira likening the protouniverse's inhabitants to ants does not improve his mood.
-->'''Odo:''' Just because we don't understand a lifeform doesn't mean we can destroy it.
* YearInsideHourOutside: Kira is dubious that life could exist in the proto-universe after just hours. Bashir points out that they have no idea how time works in this other dimension and that a few hours for them could be billions of years passing inside the proto-universe.
* YouJustToldMe: Jake thinks Sisko knows about his new relationship, saying O'Brien promised not to tell. Sisko doesn't know what he's talking about, but he indulges the conversation rather than outright say that. After Jake admits he's dating a dabo girl, Sisko starts yelling and points out he never actually said that he knew what Jake was talking about.
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