“Impulse” is episode five of season three of Star Trek: Enterprise.
Captain Archer is rushing T’Pol to sickbay. She’s getting emotional as the captain and Dr Phlox are strapping her down. Phlox says the damage is more severe than expected. He isn’t sure he can reverse it. T’Pol is going wild until she’s sedated.
One day earlier and the captain and Trip are in the command centre. Trip has been talking to Chef; people are skipping meals. Trip wants to restart movie night. The captain thinks there’s plenty of time after they deal with the Xindi. Trip hates the Xindi as much as anyone, but the crew need a little R&R. Unless the captain wants Phlox to start medicating people, they need to find a way to boost morale. Archer agrees to start again as T’Pol arrives. Thew captain explains they were seeing if the Xindi star charts would help them locate anomalies. He didn’t want to get her out of bed and their resident insomniac was looking for something to do. Hoshi contacts them from the bridge; an automated Vulcan distress call has been picked up. No response to hails.
On the bridge, Hoshi tells them it’s from the Seleya which entered the Expanse nine months ago. The call is coming from within an asteroid thicket and T’Pol reports the courses of the asteroids are unusually chaotic, perhaps due to spatial anomalies. Trip reports the asteroids are loaded with trellium ore. The captain will take a shuttlepod into the asteroids; he wants Trip to get some trellium. Perhaps they’ve given up on synthesising trellium, after what happened in the previous episode “Rajiin”. Though only one lab was blown up.
The captain, T’Pol, Reed and a MACO head in. T’Pol says the Seleya was her last assignment before Earth. It was attempting to chart the thermobaric perimeter when it was pulled in. The Vaankara was sent in to find her, and they know what happened to that.
Trip and Travis are beaming trellium ore onboard when a spatial anomaly passes through and the trellium ends up embedded in the walls of the transporter, which is now broken. Travis says they could take a shuttlepod and land on one of the large asteroids.
The Vulcan ship is drifting with no power, minimal life support and large chunks missing. But there are still biosigns. No response to hails. The shuttlepod docks. Inside, the Seleya is damaged with flickering lights and strange noises. All it needs is Reed’s tricorder to be making a regular thumping noise. The Vulcans had started adding trellium to the bulkheads. The four split up. The captain and T’Pol detects a biosign behind a door. It’s opened and a deranged Vulcan tries to brain them. He takes multiple stun hits before falling. T’Pol reports his synaptic pathways have suffered severe damage. Two more Vulcans attack.
The captain contacts Reed to warn him, just before more Vulcans attack Reed and the MACO. Fortunately, the Vulcans are only using blunt weapons. The captain and T’Pol arrive to help. They head back to the airport but two more Vulcans seal it off. The four end up fleeing. They can’t contact Enterprise and the bridge is a long way off with up to 147 Vulcans on the ship. The launch bay is on the same level but depressurised. All four bulkheads leading to the airlock have been sealed. T’Pol doesn’t look great; she says whatever happened to the crew may be affecting her too.
Travis and Trip are in the asteroid thicket trying to collect trellium ore. Meanwhile, the away team is trapped on a Vulcan ship going through Night of the Vulcan Zombies. The Vulcans might not be dead, but they don’t talk, shamble, are relentlessly pursuing them and are really difficult to put down. And T’Pol is getting worse.