Upper Michigan, USA. In the seventies, Aperture has faced financial difficulties. Because of this, the laboratory can't invite Olympians, Astronauts and War Heroes. Instead, they invited ordinary people who received $60 for participating in the tests.
This story about one of these test subjects. After some time after the arrival of the main character in the Aperture, an incident occurs, which leads to "unforeseen consequences".
The game takes place before the Portal 1 events.