“Macrocosm” is episode twelve of season three of Star Trek: Voyager.
Neelix is speaking, with many peculiar gestures, to an alien and apologising for Captain Janeway’s behaviour. Afterwards, they leave on a shuttle following a three-day trade mission to the Tak Tak. The captain says that the Tak Tak are one of the most unusual species she’s encountered, and the most unforgiving. They make the Klingons look sedate. It seems she accidentally used one of their rudest insults by putting her hands on her hips. Neelix says the gestures are ritualistic, perhaps even superstitious. Janeway thinks she should promote him to ambassador.
Voyager is not at the arranged rendezvous, and it isn’t responding to hails. It’s over a light year away and apparently adrift. When the shuttle gets there, the ship looks fine but bioelectric interference is preventing a proper scan. The escape pods are in place and there’s no sign of transporter activity.
On Voyager, sensor readings are erratic, thanks to the field, and the main computer and com systems are offline. A bioneural gel pack in the mess hall has ruptured. They head towards a bridge and discover where someone apparently abandoned maintenance in the middle of doing it. A com signal is coming from Ensign Wildman’s quarters, but they are empty. The signal is coming from Neelix’s Good Morning Voyager programme, which auto-repeats. The programme, and some food, both appear to date back 11 hours.
A sound is heard outside and a shape is seen. It is tracked to a transporter room, where a hole surrounded by a mucilaginous substance has been punched in the floor. It doesn’t contain humanoid DNA. Main power is failing and systems are starting to shut down.
Neelix and the captain head to a turbolift and a crash is heard as some lifeform enters the lift shaft. There’s a loud buzzing sound, then a tendril punches through the wall and sprays Neelix with the same compound found in the transporter room. They leave the turbolift to escape and Janeway detects crew lifeforms in a cargo bay. The compound is affecting Neelix, and Janeway leaves him to get a med kit. Neelix hears an intensifying buzzing compound and shouts for help. When the captain returns, there’s only a trail of the compound left.
Engineering is also empty and Janeway stocks up on weapons and supplies. She heads to the bridge, which is also empty, and starts working with the controls. Something is on the bridge and it creeps up on the captain as she sends a mayday. The thing lunges at her, revealing itself to be a small insect that stings her. Lifesigns have also been detected in the mess hall.
Many of the crew are lying around in the mess hall. Janeway tries to get Harry to respond, but fails. She then works on Chakotay, and finds a welt and hole on the side of his neck, through which tiny insects emerge. Something much larger is behind the captain and, although she destroys it, she gets injured as a result. Heading to sickbay, she discovers the Doctor there, armed with a phaser. He was expecting someone different.
The Doctor recaps what happened; it seems the ship has encountered a macroscopic virus. Something he never imagined would exist. Captain Janeway is the focus of much of the episode; apart from Neelix and the Doctor, the rest of the crew don’t even appear until the Doctor’s recap of how they encountered, and were affected by, the virus. With the captain and the Doctor the only ones still mobile, they need to cure the rest of the crew. The episode involves climbing through a lot of Jefferies tubes, causing the Doctor to ask just who designed the ship.