Kira, O'Brien, Odo, and Worf confront Quark about illegal advertisements that he inserted throughout Deep Space Nine's computers. The most egregious is replacing all the cups in the replicators with mugs that play a jingle each time they're tipped. Kira warns Quark that he'd better remove all of his ads by the time she gets back from her mission into the Gamma Quadrant with Dax and Bashir.
While on the mission in the Gamma Quadrant, they receive an automated distress signal from a planet on the edge of Dominion space. When they beam down to investigate, they find a ruined city and people with bluish lesions on their faces. They then encounter a woman with red lesions who collapses in agony in front of them and begs to be taken to "Trevean." They find Trevean's hospital, where she's taken away. Trevean explains that all of his people, the Teplans, were infected with "the Blight" by the Dominion as punishment. Victims have blue lesions and may live for years or decades before the lesions "Quicken" and turn red, indicating an impending, painful death. Mothers pass down the disease to their children, and everyone dies from it. Bashir and Dax, however, are at no risk.
To Bashir's horror, he discovers that Trevean is not a doctor so much as a euthanizer, whom residents visit when their Blight quickens to receive a painless death. The population has lost all hope of a cure and simply wish to limit their suffering. Bashir and Dax offer to make a go of it and try to recruit test subjects. No one seems interested, and Trevean accuses them of peddling false hope, but they find their first volunteer in Ekoria, a pregnant mother who wants to live long enough to give birth. As they set to work, Kira warns them that a Jem'Hadar patrol will arrive in about a week, so time is limited.
Bashir quickly whips up an antigen and begins treating the Teplans under his care. But as he makes some routine scans, his Quickened patients' symptoms progress rapidly, forcing Trevean to come and ease their passing with toxic cocktails. Bashir realizes that the disease reacts to electromagnetic fields, an intentional design from the Dominion to prevent the Teplans from rebuilding their civilization. All of Bashir's patients save Ekoria are dead, and time is up. Bashir is despondent, but Dax convinces him that there still may be a cure. He resolves to stay behind as Dax and Kira return to the station.
Bashir cares for his only remaining patient, the pregnant Ekoria, who is now in the initial stages of Quickening and wants to survive just long enough to give birth. Trevean believes that Bashir is making her suffer needlessly and offers her his mercy, suggesting that her child could die "knowing only peace" rather than suffer the Blight. She refuses. A few weeks later, Bashir induces labor on Ekoria, and she delivers a baby boy without any sign of the Blight. Bashir realizes that the antigen he created is actually a vaccine that helped Ekoria's son fight off the Blight. Ekoria, finally realizing that her son will not suffer from the disease, dies in exhaustion.
Trevean and his followers are astonished at the first Blightless child they've ever seen. Trevean volunteers to manufacture Bashir's vaccine and administer it to every pregnant woman on the planet. The Teplans begin to celebrate an end to the Blight, but Bashir stands away, not feeling like celebrating. Back on the station, Sisko gives Bashir his commendations for helping the Teplan people, but Bashir is not satisfied. The next generation of Teplans may be born free of the Blight, but the people already afflicted are still doomed to horrible deaths. Bashir stays late into the night, alone, continuing to search for a cure.
Tropes:
- Artistic License – Medicine: It's extremely premature to call Bashir's antigen a successful vaccine. For one thing, this vaccine was only confirmed to be successful in one person, and while it worked for Ekoria's son, there wouldn't be any guarantee that it would work with other pregnant women, especially those who have progressed later in term than Ekoria has. In addition, a virus like the Blight already existing in the mother's body would likely infect the fetus during the early stages of pregnancy, yet a vaccine administered in the late stages of pregnancy appear to be successful. The episode seems to reference this at the end when Bashir is running simulations on his computer to find out exactly what happened.
- Bittersweet Ending: Try as he might, Bashir cannot find a cure for those presently suffering from the blight. However, he does accidentally create a vaccine to prevent babies from being born with it if administered to pregnant women, thus saving the next generation (and those in the future).
- Break the Haughty:
- Bashir goes down to the planet expecting to have the blight fully cured in just a few days. Boy, is he wrong. By the end of the episode when the first baby born free of the blight is presented to the populace, Bashir wants nothing to do with the celebration and prefers to stand off to the side. Later, when Sisko is offering his congratulations, Bashir sharply retorts that he doesn't deserve any.
- The Teplan civilisation as a whole. Something the Teplans did likely pissed off the Dominion to the point they introduced this horrible disease, as this is the only instance of the Dominion acting in such a manner.
- Cold-Blooded Torture: Implied to be the fate of those who have falsely promised help to those dying of the blight.
- Cruel and Unusual Death: The whole point of the blight.
- Cruel Mercy: This planet resisted the Dominion, and as punishment the Jem'Hadar infected them with blight that they can't cure, has a hundred percent infection and mortality rate, and will eventually kill the victims at a random point in their life. To top it all off, the virus is made worse in the presence of electromagnetic fields, meaning that the Teplan civilization had to renounce technology and revert to medieval standards to just survive. Thus, instead of simply killing their enemies outright like they usually do, they condemned the populace to die a slow death.
- Death by Childbirth: Sort of. Ekoria's already dying of the blight, but giving birth finishes her off.
- Determinator:
- Ekoria, now in the stages of Quickening, is determined to survive until her child is born, even refusing Trevean's "treatment" and enduring suffering up until the birth of her son and her death.
- Bashir doesn't let Trevean's threats or the danger of Dominion attack dissuade him from searching for a cure. Even after developing a vaccine he continues his search for a cure on the station.
- Dystopia: We don't get a name for the planet itself, but it's sure as hell this trope thanks to the blight.
- Earworm: "Come to Quark's! Quark's is fun! Come right now! Don't walk, run!"
- Face Death with Dignity: Trevean's clinic euthanizes those who have quickened and ensures they are as comfortable as possible.
- Freeze-Frame Bonus: Quark's Mug when the angry Worf holds up his in the opening scene. Look closely, and you’ll see that Quark's offers free refills...with the typically Quark-esque disclaimer "limit one per customer".
- Heroic BSoD: Bashir goes into one when his attempts to help only make things worse. He comes out of it when they finally yield some measure of success.
- Hope Spot: It looks like Bashir is making excellent progress finding a cure for the blight...and then things really go to hell.
- Human Aliens: Outwardly at least, the Teplan inhabitants look identical to humans (or would, if it weren't for the lesions from the blight), although their physiology is very different to either humans or Trills, meaning the disease can't harm Bashir or Dax.
- Implied Death Threat: Kira delivers one to Quark:"If all your little advertisements aren't purged from our systems by the time I get back from the Gamma Quadrant, I will come to Quark's, and believe me, I will have fun."
- Informed Attribute: Trevean is said to have survived the Blight longer than anyone, meaning he's the oldest Teplan alive, but group shots of the Teplans reveal people who look obviously older.
- Kick the Dog: Simply because the people of this planet resisted the Dominion 200 years ago, the Jem'Hadar made an example of them, by infecting them with a "blight" which they are born with and which "quickens" itself randomly in a person's life, creating red lesions when it becomes active, and killing them shortly after in particularly painful fashion. That'd be bad enough, but it turns out the electromagnetic field from medical instruments (as Bashir learns the hard way) amplifies the virus, and causes it to mutate. These people must've really, really pissed off the Dominion.
- Layman's Terms: Dax translates Bashir's Technobabble for Ekoria.
- Mandatory Line: Sisko doesn't appear until the final scene. Worf, O'Brien, Quark, and Odo only get a couple of lines in the teaser.
- Meaningful Name: Trevean is an anagram of "veteran" and Ekoria is a (loose) anagram of "rookie." The writer, Naren Shankar, said that kind of thing helps him with characterization.
- Medieval Stasis: Enforced by the blight. Electromagnetic radiation makes the disease rapidly progress, so their once advanced civilization had to regress to survive. Bashir discovers this when all his equipment makes the disease even worse and he has to go low-tech to continue his work.
- Mercy Kill: Trevean's actual job. Bashir initially mistakes him for a doctor.
- Mood Whiplash: The cold open is Kira, Odo, and Worf acting as though Quark sneaking an annoying advert into the ship's systems is a crime equivalent to high treason.note This hilarious introduction soon segues into a story about... the protracted genocide of a planet across generations and Julian's largely futile efforts to put an end to it.
- Moral Pragmatist: Many have tried and failed to cure the plague, and Doctor Trevean has given up hope of a cure and provides euthanasia because it's the only kindness he thinks is possible. This infuriates Bashir, who risks everything to work on a vaccine. As soon as hard evidence surfaces that the vaccine works, Trevean drops his arguments about euthanasia and helps Bashir distribute the vaccine.
- Nice Job Breaking It, Hero: Bashir's medical equipment only makes the disease worse.
- Noodle Incident: The Dominion is known for conquering and destroying civilisations that go out of line, but to resort to this kind of genocide means that the Teplans must have done something to force the Dominion to react in this manner.
- Paranoia Fuel: In-Universe — nobody knows when they'll quicken.
- "Ray of Hope" Ending: Bashir fails to cure the people living with the blight, but he accidentally figures out how to immunize their unborn children.
- Someone to Remember Him By: When Ekoria lost her husband, she was simply counting down the days to her own quickening until she realized she was pregnant. Her determination to survive long enough to give birth is what drives her to seek Julian's help.
- Surprisingly Realistic Outcome: This episode is a Deconstruction of a common plot in Star Trek—a long-standing medical problem is cured by the miracle of Starfleet medicine. More likely, a disease that has gone uncured for so long won't be so easily resolved—and indeed, Bashir never finds the cure he hoped to find. He still has more success than anyone before, but the full benefits of his discovery won't be felt for another generation or so.
- Wasteland Elder: Trevean, a particularly cynical example.
- Truth in Television:
- While antigens are actually part of a vaccine, the episode doesn't treat Bashir's antigen as a vaccine until the very end when it is revealed that it can be used on pregnant women. While it seems odd that antigens would be used in this fashion, the notion that a vaccine can be used on an existing infection does have some precedence as Shingles is a disease arising from a dormant infection from Chicken Pox, and we do have Shingles vaccines available today.
- The DTaP vaccine is an example of a vaccine that is administered to pregnant women to help protect their unborn children from infection from Pertussis, which is the bacteria known to cause Whooping Cough, a condition that can be fatal to newborns.
- Bashir standing off to the side as Trevean shows the first blight-free baby to the Teplan populace is in reference to Jonas Salk, the creator of the first polio vaccine. He wanted no credit in its creation and wanted nothing more than to help prevent a disease that at the time, had ravaged millions.
- Villainy-Free Villain: Trevean obstructs Bashir for most of the episode, but only because he believes that Bashir is causing unnecessary suffering by promising a cure that he cannot possibly deliver (which, according to him, has happened before and made his people suspicious of outside help). When Trevean is proven wrong, he instantly supports Bashir's vaccine.
- What the Hell, Hero?: Dax gives a beautiful one to Bashir, telling him that it's pure arrogance to think that there isn't a cure for the Blight simply because he couldn't find it. Funnily enough, this is in the wake of Bashir chastising himself for arrogance of a different kind — thinking that he could find a cure so easily for a disease that had gone uncured for so long.
- "You!" Exclamation: Worf, when he confronts Quark over a mug of prune juice that is basically an advertisement for Quark's bar.Worf: I ordered a glass of prune juice from the replicator in the Defiant's Mess. THIS (raises a mug with Quark's advertisements printed all over it) is what it came in! (he turns it to the side, and it plays an audio version of his ad)
