Hoshi is helping Phlox feed his pets, only to be stunned when a tribble turns out to be the prey of one of them. She then gives him a transmission from the Denobulan Science Academy, causing him to look grim when he reads it. He discusses it in the situation room with Archer, Trip, Malcolm, and Travis, revealing that the academy asked Enterprise to find three geologists who went missing in some caves. The reason Phlox is worried is because the caves are on a planet called Xanatoras, which has a new government declaring all off-worlders must leave within three days.
Trip, Malcolm, and Travis are sent into the caves to try to find the geologists, and if they can't within 36 hours, they have to get back to the ship. As the three men go down into the caves, Enterprise overhears an alien transport ship and a Xanatoras flight controller talking— the transport ship has a reactor leak, but the Xanatorans aren't letting them land. Archer decides to help and Phlox begins treating the patients, but one of them refuses treatment.
Outside sickbay, Phlox explains to Archer that his patient is Antaran, a species which the Denobulans used to have animosity with. This causes a conflict between Phlox (who doesn't want to treat the Antaran since Denobulans believe all patients' wishes should be respected) and Archer (who wants the patient to be treated).
Archer talks to the Antaran, whose name is Hudak, to make him aware of his situation, but Hudak, even learning that he will probably die without medical attention, still refuses treatment. He tells Archer to look up the history between the Antarans and the Denobulans, which Archer does. He then talks to Phlox, who notes that both species are raised to believe the other is evil. Archer encourages Phlox to talk to Hudak to prove that he's not what his people believe him to be.
The away team finds some Denobulan equipment containing rock samples. They climb down and enter a tunnel, trying to find the geologists by following the geological features that they're likely to find interesting. Malcolm trips and falls, causing the other two to fall as well as they're tied together. After a struggle, Trip and Malcolm stabilize themselves uninjured, but Travis ends up breaking his leg and tearing his ligaments.
Back on the ship, Phlox monitors an unconscious Hudak. Hudak wakes up and is very suspicious of Phlox, thinking he wants to kill him. He asks Phlox if he taught his own kids to hate Antarans, causing Phlox to angrily snap at Hudak and then go to the mess hall to cool off. There, he meets T'Pol, who asks him about the patient. Phlox replies that Hudak is "dying to prove a point" and reveals that he tried his best not to raise his children to hate Antarans.
While Travis lies on the floor of the cave nursing his injury, Trip and Malcolm walk onward and find the scientists. However, despite being explained the situation, they refuse to leave. They claim that the government will likely change soon, which is why they don't want to leave, but Trip has none of that and threatens to tie them up, causing them to relent and agree to go.
Phlox again talks to Hudak about starting the procedure, but Hudak again denies it. Phlox brings back the previous conversation, revealing that he himself was fed prejudice as a child and the propaganda about Antarans gave him nightmares, but he shed his prejudice as he grew up and tried to raise his children not to hate Antarans. This worked with all but one of them, his youngest son Mettus. Phlox encourages Hudak to drop his own prejudice to make an example for his children and Phlox finally does.
Trip and Malcolm bring the scientists back through the cave, at one point feeling a rumbling, which Malcolm suspects to be weapons' fire. He's proven right when the Enterprise detects shooting, but not towards the ship or the Denobulans. Archer hails the government, pointing out that his away team still has 90 minutes left, then he threatens to open fire himself if they don't cease fire. Thus, they cease fire, allowing Trip, Malcolm, and the scientists to leave, taking Travis with them.
Archer escorts Hudak, who has now gotten treated, to the transport, asking if it's a problem that the geologists are on the same transport. Hudak replies that it's not a problem. Later, in sickbay, Phlox, wanting to eliminate the problem of indifference to hatred, begins writing a letter to Mettus.
Tropes in this episode include:
- Absolute Xenophobe: The Xantoras government expels all offworlders after taking power.
- Call-Back: In "A Night in Sickbay", Phlox mentioned being estranged from two of his sons. Here, he explains what happened with one of them.
- Counting to Three: Trip pulls this on one of the Denobulan geologists who stops to collect rock samples.Trip: If you don't get moving in the next three seconds, I'm gonna take my phase pistol and shoot you in the ass!
Denobulan: These are priceless!
Trip: (starts reaching into his bag) One...two...
(the cave starts shaking from weapons fire)
Trip: GO! - Dark and Troubled Past: For an entire species. The Denobulans we meet are generally kind, friendly and seem entirely peaceful and tolerant. We learn here that they have a history of warfare and violence which they're clearly embarrassed about, and that there are still streaks of Fantastic Racism alive in their society.
- Does This Remind You of Anything?: Phlox's situation is akin to, for example, an Israeli doctor treating an Arab patient.
- The patient's comments suggest it's a lot closer to a Nazi doctor treating a Jewish patient, with Archer encouraging the patient to just trust the professionalism of the Nazi doctor. And then the doctor getting mad the patient keeps reminding him of the past and move past it.
- The complicated and bitter history between Denobulans and Antarans since their last war is reminiscent of the strained relationship between China and Japan after the Second Sino-Japanese War.
- Evil Tainted the Place: Phlox's grandmother wouldn't let him visit a planet that the Antarans had once occupied, claiming that the planet was "spoiled". When he grew up, Phlox said, "Screw that" and brought his own children there.
- Fantastic Racism: Denobulans and Antarans hate each other, to the point where Hudak would rather die than let Phlox save his life.
- Injured Limb Episode: Downplayed; Travis's broken leg is a sub-plot.
- Jaw Drop: Hoshi goes slack-jawed when Phlox feeds a tribble to one of his creatures, and she briefly looks like she's about to throw up.
- Just in Time: A rare aversion — rather than escaping the planet just before the deadline, the away team and the Denobulans escape two hours after the deadline.
- The Main Characters Do Everything: Mayweather has extensive climbing experience in caves, and is a natural choice for the rescue mission. Apparently there were no other experienced climbers aboard, as main characters and climbing rookies Tucker and Reed round out the landing party.
- My Greatest Failure: Phlox taught his children not to succumb to prejudice, but it was clearly lost on his youngest son, Mettus.
- O.O.C. Is Serious Business: Phlox's usual upbeat demeanor crumbles in one conversation with the Antaran, to the point that Phlox - Phlox - starts yelling at him.Phlox: I have tried to treat you with respect, but I refuse to listen to these insults! You're the reason we haven't been able to put the past behind us! You have kept this hatred alive! No Denobulan would want to be in the same room with you!
- Plummet Perspective: Trip, Malcolm, and Travis get a good long look at how far down the cavern goes while they're spelunking.
- Prejudice Aesop: This episode discusses prejudice and why it's wrong.
- Racist Grandma: When Phlox was a teenager, his grandmother refused to let him go on a vacation to a nearby planet because the Antarans had once lived there.
- "Ray of Hope" Ending: The episode ends with Phlox composing a letter to his estranged son Mettus in the hopes of mending the rift between them.
- Relative Button: Phlox loses his cool when Hudak provokes him by asking if he taught his children to hate Antarans like he was taught as a child. As Phlox would later reveal, it reminded him of how he tried and failed to keep his youngest son Mettus from succumbing to anti-Antaran prejudice.
- Shot at Dawn: Trip tries to warn the Denobulan geologists that they might be executed if they don't leave Xantoras.
- Skewed Priorities: When the rescue team informs the geologists that they'll be imprisoned or killed if they refuse to evacuate, they reply that their research is going too well to abandon. Their strategy is to remain in the cave until the government changes, and they're allowed to come out.
- That's an Order!: Archer orders Phlox to save Hudak, even though he refused treatment. Phlox refuses to follow that order unless Hudak changes his mind.
- Took a Level in Kindness: Phlox believed the anti-Antaran propaganda he was told as a child and it caused him to have nightmares about Antarans, but as he grew up, he realised the stories were wrong and outgrew his prejudice.
- Trying Not to Cry: When T'Pol commends Phlox for teaching his children to embrace other cultures, Phlox is nearly in tears as he replies that he tried his best, thinking of how he failed to do so with his youngest son Mettus.T'Pol: Your children are fortunate to have a father who taught them to embrace other cultures.Phlox: [Sadly, near to tears] I certainly tried...
