“Cause and Effect” is episode eighteen of season five of Star Trek: The Next Generation.
The Enterprise is in serious trouble. One nacelle is venting drive plasma. Riker orders the crew to escape pods. Core shutdown fails, as does the attempt to eject it. Captain Picard is ordering the crew to abandon ship as it explodes.
The Enterprise has entered the Typhon Expanse and will be the first ship to chart the region. Data, Riker, Worf and Dr Crusher are playing poker. The doctor seems a little distracted. It comes down to her and Riker, but the commander was bluffing. He asks how she knew; she just had a feeling. Then she’s contacted from sickbay; Geordi needs her help.
Geordi had ended up feeling dizzy and nearly fell off the catwalk. The doctor says he has all the symptoms of an inner ear infection, but no physical evidence. She suggests he’s been working too hard. Dr Crusher is going to give him a hypospray, but as she’s doing it, she asks if he’s had the symptoms before. No. But she feels like they’ve discussed this before and given him a hypospray for dizziness.
Later, in her quarters, Dr Crusher gets ready for bed. When she turns the lights out, she hears a sound like many people talking and jolts up.
The next day Geordi is briefing most of the senior staff in the conference room about the mission. At the end of it, Dr Crusher reports hearing voices in her room whilst she was alone. She thought she was imagining it, but ten other people reported hearing voices at the same time. There’s nothing in the sensor logs and Troi sensed something. Then Worf contacts them from the bridge; there are unusual readings.
Ahead of the ship is a distortion in the space time continuum. Manoeuvring thrusters don’t respond and they can’t back off. The distortion field is fluctuating and main power goes down. There’s an energy build up in the distortion field, then a Starfleet ship emerges. They are probably not the first in the Typhon Expanse. Shields don’t work and they can’t avoid the other ship, which is on a collision cause and not responding to hails. Captain Picard asks for options; Riker suggests depressurising the main shuttle bay and Data using the tractor beam. The tractor beam is used, but the other ship clips the nacelle. And this is where we entered, with the ship exploding.
The Enterprise has entered the Typhon Expanse and will be the first ship to chart the region. Data, Riker, Worf and Dr Crusher are playing poker. The ship is stuck in sort of temporal loop. As they repeat the loop, people are getting sensations of deja vu – or the Klingon equivalent – and remembering bits that have happened before. Which means they do work out what is going on, but each time the loop repeats they’re starting over again. Somehow, they need to solve the problem and communicate this to another loop. As such, much of the episode is repeating events, though with some minor changes.