“Revisions” is episode five of season seven of Stargate SG-1.
Planet P3X289, as viewed through the MALP’s camera, is uninhabitable and has a poisonous and corrosive atmosphere. There is a dome, though, inside which is a pleasant place with people living there. The survivors are technologically advanced, and say that the dome was constructed after the world was rendered uninhabitable by the poisoning of the environment. The people living in the dome have access to all their civilisation’s combined knowledge through something called the Link; this being an item of technology that is placed on the head.
Then, people start disappearing. They are wandering out through the dome into the poisonous exterior of the rest of the planet. Which basically means that they are committing suicide, but why are they doing this? Sam sees the computers doing something odd, but the locals don’t believe her. The people also don’t remember the missing. This is probably connected to the Link, as everyone is wearing it. Sam also detects some power fluctuations in the dome forcefield, but again, the locals don’t believe her. The dome also seems to be shrinking.
Can SG-1 save everyone before they all die? Especially as the natives don’t realise that anything is actually going on.