We cut to the previous day, where Trip is in the mess hall, expressing concern over the crew's morale. He suggests either reintroducing movie night or giving them medication. T'Pol enters and they begin talking, when Hoshi calls them all to the bridge, having gotten a Vulcan distress call and no response to her hails. They go to the bridge, and T'Pol recognises the source as a Vulcan ship called the Seleya.
They find the Seleya inside an anomaly-ridden asteroid field and discover that the asteroids contain trellium ore. Archer asks Hoshi to wake Malcolm and send him to the launch bay and Trip to get some ore, then he, T'Pol, Malcolm, and a MACO named Hawkins go into a shuttlepod and into the asteroid field. T'Pol reveals that she was once deputy science officer on the Seleya, only for it to be pulled into a "subspace eddy" and never heard from again. Meanwhile, Trip and Travis are beaming asteroids onboard to try to get at the trellium, but the transporter glitches out, causing the asteroids to materialise fused into the walls. Thus, they try to retrieve more asteroids in a shuttlepod while the transporter is being repaired.
The away team arrives at the Seleya to find the main power is down, the life support is barely up, and there are bio-signs but they don't respond to com signals. They board it, and Malcolm finds liquid trellium spilled on a bulkhead. They split up into pairs, and Malcolm and Hawkins find Vulcan blood next to a terminal. Archer and T'Pol hear someone knocking at a jammed door and open it to find a sickly-looking Vulcan man who attacks them with a blunt weapon. Archer pins him to the ground, then the Vulcan guy scratches him, and Archer and T'Pol both shoot him in succession, which stuns him.
As they try to take the unconscious Vulcan man back to the shuttlepod, Archer and T'Pol are attacked by more Vulcans wielding identical weapons, all of whom need to be phasered twice in order to pass out. Archer warns Malcolm, who is promptly attacked (along with Hawkins) by more feral Vulcans. They fight, which eventually leads to one of the Vulcans trying to strangle Malcolm, but thankfully Archer comes to the rescue. He suggests they retreat when more Vulcans show up, and Hawkins sets his phase-pistol on "kill" but is convinced to set it back to "stun". They head to the docking port, only to find two Vulcans with cold stares, who seal it off. Three Vulcans go in through the back door, one of them using a welding tool as a weapon, and the away team escapes up a ladder and closes a hatch.
Archer tries to contact Enterprise, but he can't. T'Pol says they might be able to contact Enterprise from the bridge, but it's seven decks above and there are 147 feral Vulcans on the ship. Malcolm suggests using one of the Seleya's shuttles, but the bay has been decompressed, so they head off to sickbay to treat the injured Hawkins. Meanwhile, Trip and Travis find a large asteroid and land on it.
In Seleya's sickbay, a Vulcan man jumps from the ceiling, who Malcolm stuns. He then starts treating Hawkins, when Archer asks who the Vulcan guy in the isolation pod is. T'Pol explains that he's Solin, the chief engineer, but begins losing control of her emotions. They go through an access tube (with T'Pol being a bit shaky) and find debris blocking the way. Archer and Malcolm squeeze through and Archer tells Hawkins to look after T'Pol. While Archer and Malcolm head to engineering, Hawkins gives T'Pol a drink of water and asks how Vulcans could be aggressive with no emotions. T'Pol explains that Vulcans do have emotions; they just suppress them, and that Vulcans, in fact, used to be extremely violent. Archer and Malcolm reach engineering, where Archer is attacked by more Vulcans. They knock them out, then call Hawkins and T'Pol over.
On the asteroid, Trip and Travis have gotten their box of ore, but then an anomaly causes the asteroid to change course and a larger asteroid moves towards them. Back on Seleya, Archer discovers the transceiver is down, T'Pol is even shakier, and Malcolm has encrypted the locking mechanisms on the doors.
Trip and Travis arrive back on Enterprise and Archer sends a com message, asking them to pick them up. Unfortunately, the shuttlepod is broken and will take several hours to repair. Archer sends some data to Phlox to analyse, then T'Pol gets to work rerouting the bulkhead controls to engineering. However, when she gets an electric shock, she angrily throws the circuits at Archer and Malcolm and accuses them of trying to undermine their work. Malcolm suggests causing an overload in the power grid, which would override all systems including the bulkhead mechanisms. T'Pol vetoes the idea, since the warp core is unstable, so it will probably shut down the antimatter containment and cause a warp core breach. Then, believing that Archer is trying to kill the Vulcans as revenge, she points a phase-pistol set on "kill" to him. There's a bang at the door, causing everyone to turn around and Archer to disarm T'Pol and point his phase-pistol at her.
Meanwhile, Phlox and Trip examine the bio-scans and determine that the large amounts of trellium are what's causing the Vulcans' erratic behaviour. He contacts Archer and tells him that unfortunately the Seleya's crew can't be saved, but that T'Pol can. Then, the communication is cut off and poisonous gas starts to flood the room. Malcolm activates the overload and they escape through an access tube. They find a hole in the floor that leads to space, but luckily are able to bridge the gap. Archer has to stun T'Pol and Vulcans attack Malcolm and Hawkins, but they manage to cross it.
They reach Shuttlepod 1 to find the docking clamps locked, but thankfully Shuttlepod 2 comes to the rescue. The shuttles then dash away as the Seleya blows up. Archer orders Trip to put the trellium he and Travis found in a bio-hazard locker, while T'Pol recovers in sickbay.
Days later, the crew has movie night, followed by a tactical alert. T'Pol strides down the corridor and is attacked by a Seleya crewmember... only, she was just having a nightmare.
Tropes in this episode include:
- Asteroid Thicket: A rather unusual example, as the asteroids are moving in ways that T'Pol describes as "chaotic"—possibly a result of the trellium in them, or spatial anomalies.
- Bittersweet Ending: T'Pol is still recovering, but she's on the mend.
- Call-Back: The episode fills in the backstory of the Vaankara from "The Expanse". After the Seleya became trapped in Delphic Expanse, the Vaankara was assigned to find and rescue them.T'Pol: [to Archer] You already know what happened to that crew.
- Captain Crash: Well, Ensign Crash — Trav's less-than-stellar landing on the asteroid, though Trip is far less critical.Travis: I hope you won't write that landing up in your log.
Trip: Are you kidding? I'm gonna recommend they give you a medal. - Cassandra Truth: T'Pol doesn't believe Archer when he claims he isn't trying to kill the Vulcans.
- Dead Man Walking: According to Phlox, it's too late to treat the Vulcans on the Seleya. They're barely able to help T'Pol.
- Genre Savvy: During movie night, Phlox believes a detective character will turn up later in the story. When Trip says the character was killed in a house fire, Phlox cites Not Quite Dead and Faking the Dead tropes to back up his claim. The movie is interrupted before we can find out if Phlox was indeed savvy or not.
- I'll Kill You!: Crazy T'Pol screams that she'll kill Archer and Phlox.
- I'm a Doctor, Not a Placeholder: Inverted; T'Pol is scanning a Vulcan suffering from trellium poisoning, while she herself is clearly being affected.Archer: Any idea what's wrong with him?T'Pol: (tersely) I'm not a doctor.Archer: But you are my science officer. I need to know I can depend on you.
- In Medias Res: The Teaser shows Archer and Phlox bringing T'Pol to Sickbay while she's going completely bonkers. The episode then shows what led to that.
- Irony: While visiting a recovering T'Pol, Archer explains they've got all the trellium they'll ever need to protect the ship, but it's been determined that's what poisoned the Vulcans.
- The Needs of the Many: After being told why the Vulcans turned, T'Pol volunteers to be dropped off on the nearest inhabited planet so that the crew can proceed without damaging anomalies getting in the way. Archer won't hear of it, despite T'Pol's insistence that one crewmember isn't more important than everyone else or the overall mission.
- No One Gets Left Behind: Archer won't even consider dumping T'Pol on some random planet, saying they'll find another way to make things work.
- Not Herself: T'Pol becomes affected by the trellium, showing visible signs of fear and panic.
- Not So Stoic: The main symptom of the trellium poisoning is when the usually stone-faced Vulcans start expressing fear and later aggression.
- O.O.C. Is Serious Business: You know it's serious when Archer and T'Pol are arguing and Archer is the logical one.Archer: We're here to save these people.
T'Pol: You're lying. You want to kill them!
Archer: If that's true, then why would I keep our weapons on "stun"? It's not logical. - Our Zombies Are Different: The trellium turns the Vulcans into zombies IN SPACE!
- Out-of-Genre Experience: On the audio commentary, director David Livingston remarked this episode was a fun shift switch from the typical fare to a horror movie.
- The Paralyzer: The MACO takes his rifle off stun when the stunned Vulcans get back up again. Archer and T'pol have to order him to belay that.
- The Paranoiac: One of the symptoms of T'Pol's trellium poisoning is her belief that Archer wants to kill all of the Vulcans.
- Real Life Writes the Plot: The final nightmare twist was filmed after the episode came back short.
- Red Shirt: Subverted with Hawkins. He's the only non-main character on the away mission, but he survives.
- Screw the War, We're Partying: Trip tells Archer how low morale has become among the crew. He restarts movie night so that the crew can have some way to blow off steam.
- Shout-Out: The brief clip of the movie night offering is taken from the 1950 noir flick, Appointment with Danger. note
- Sound In Space: The asteroids crash against each other.
- Tantrum Throwing: When trellium-poisoned T'Pol gets angry at Malcolm for ruining a set of circuits that they need to open a door by accidentally installing them in the wrong slots, she pulls them out and throws them at Archer and Malcolm.
- Teleporter Accident: An anomaly passes through the transporter at the worst moment, and the rock that Trip was beaming up materializes all over the walls. He even notes "this'll be a new one for the maintenance team."
- Unobtanium: Enterprise finds the Seleya in an asteroid field that's rich with trellium ore. Unfortunately, it turns out that trellium is deadly to Vulcans.
