Archer and Shran go to Andoria to find a link to the Romulan drone pilot, while Admiral Valdore is determined to destroy Enterprise at all costs.
- All for Nothing: When Phlox determines that the telepresence unit is too dangerous for Jhamel to use, Archer laments that their trip to Andoria was for naught. Subverted later when Jhamel succeeds in using it anyway.
- Attack Pattern Alpha: The Romulan drones use Attack Vector 1-7-7 against Enterprise.
- Bad Dreams: Jhamel has nightmares about her brother being locked in a cage and calling out to her to help.
- Big Sister Instinct: While it's never established who the elder sibling is, Jhamel is willing to do whatever is needed to save her brother, Gareb.
- Birds of a Feather: Jhamel instantly picks up on Shran's powerful feelings of loss and says that she knows how it feels.
- Don't You Dare Pity Me!:
- Shran's opinion of Archer helping him in consideration of his temporarily-severed antenna is "hands off, pinkskin."
- The admiral tells the story of his downfall from the Senate for questioning the need for conquest. Nijil expresses sympathy, but the admiral says that he's not fishing for pity, he's trying to make a point about service to the Empire.
- The Dulcinea Effect: Trip objects to to T'Pol testing the device on herself, claiming that it's because she's presently in command.
- Flawed Prototype: The telepresence unit that Trip and T'Pol build to disrupt the Romulan marauder. It ends up being incredibly dangerous to the user.
- Hand Wave: Jhamel can tell that Shran has blue skin despite being blind. She avoids explaining how by saying that she's not good at science.
- Heroic Sacrifice: Gareb turns the two drone ships against each other and is shot by Valdore.
- Hoist by Their Own Petard: As Senator Vrax notes, their mission to destabilize the quadrant has ended up uniting the local powers against a common enemy.
- Human Subspecies: The Aenar are a subspecies of Andorian. The differences with the Aenar is that they're blind, have white skin, and have telepathic powers.
- Literal-Minded: When Trip asks what went through T'Pol's mind when she was convinced they would die while collapsing the control sphere in the Expanse, she replies "whether to transfer auxiliary power to the deflector array" as opposed to something emotionally meaningful.
- Never Found the Body: Jhamel says this of Gareb when he disappeared a year ago. It's why she now believes that he was abducted.
- Only a Flesh Wound: Twice, both for Shran, though one is backstory.
- When traveling through an ice tunnel with Archer they come across small holes created by ice-worms generating heat to migrate, and Shran relates the story of falling into one of their nests when he was 15, suffering third degree burns on over half of his body. Granted, he's Andorian with different physiology and it's the future, but that's usually barely survivable with prompt medical treatment, and in the best case results in severe disfigurement and permanent mobility restriction from the scar tissue, but the way it's mentioned he might as well have broken his arm. (In addition, it was implied last episode that Andorians are more susceptible to infection and death from such injuries than humans would be.)
- A short time later, Shran's insistence on making his own way despite his temporary unsteadiness backfires when he tumbles off some stairs and impales his right calf on an icicle. We Have to Get the Bullet Out is employed and the leg is moved off of the icicle and bandaged over his clothes, but the icicle should have done massive damage; that sort of thing can't just be patched up with some gauze, and could lead to a human bleeding out in minutes, especially with the icicle no longer providing pressure. The only major effect on Shran is that he can't walk until treated.
- Perfect Pacifist People: The Aenar only choose leaders when one is needed and decline to give Archer and Shran assistance to find Gareb because, although they acknowledge that he's the marauder's pilot and abhor the fact, they don't want violence used to stop him. Shran isn't impressed, but Jhamel volunteers to help.
- Professor Guinea Pig: T'Pol insists on testing their own telepresence device
- Punch-Clock Villain: Nijil, the Romulan scientist attached to the operation. He shows concern for Gareb and is saddened when he's killed.
- Put on a Bus: Shran tells Archer that he doesn't expect to be awarded with a new ship, so he probably won't see them for a while. He does wish him well and tells him to stay out of trouble.
- Had ENT been renewed for a fifth season, Shran would have joined the main cast by serving as an advisor.
- Red Oni, Blue Oni: Vulcan is a desert planet, Andoria is an ice moon. No wonder they don't get along.Shran: The Vulcans say the desert teaches men the meaning of endurance. But it's the ice that forges real strength.
- Screw the Rules, I'm Doing What's Right!: Jhamel defies the Aenar leader to join Archer and Shran in their search for Gareb.
- Slippy-Slidey Ice World: We finally visit Andoria, and find that it's a frozen moon of a gas giant. Not that Shran minds.Archer: (looks at scanner) 28 below?!
Shran: Lucky for you, it's the middle of summer!
- The Not-Love Interest: Shran and Jhamel form a close bond and become very affectionate and emotionally supportive of each other, since they've both lost someone they care about. It never goes beyond that in the episode; although it turns out they became each other's mates and had a daughter by the time of These Are The Voyages...
- This Explains So Much: Shran can't resist making this crack when Jhamel looks into Archer's mind.Jhamel: You have an interesting mind, Captain. Many facets.
Archer: Thank you.
Jhamel: Some of those facets are in conflict.
Shran: That explains a lot.
- Underground City: The Aenar settlement is buried beneath the ice. According to Shran, this is typical of all Andorian cities, as they take advantage of geothermal heat.
- Unfinished, Untested, Used Anyway: The makeshift telepresence unit that Trip builds. T'Pol actually does test it, but only minimally, and not enough to guarantee its success when used by an Aenar. Sure enough, Jhamel nearly suffers brain damage when she uses it.
- Wham Line: At the end, Trip tells Archer that he wants to transfer to Columbia.
- You Have Failed Me: Vrax worries that if the drone project fails, it will mean his head.