Theta is a mod set around an alternate 1970s Aperture, they've diversified their stock, struck rich on minerals mined from deep below the salt mines, and are dominating all forms of research, from human to animal to the metaphysics of the universe; if there's a question, Aperture Innovators will solve it! And you, a simple file clerk, have should have no influence over anything. In a perfect world that is...
Aperture has begun to watch its test-subjects, however due to misplaced trust the Observer Stations are a lot more 'open' and 'homely', with some staff going so far to say they are 'A terrifying idea'.