chell and glados end up in the ruins of aperture science laboratories, started in the 1950s. while exploring the area, recorded messages by aperture science founder cave johnson and his secretary caroline tell the history of the company and explain the many dangerous tests performed there. as chell moves further up in the labs, time moves forward as well, into the 1970s. cave reveals that the company is bankrupt and must use homeless people as test subjects rather than the astronauts and olympic athletes they had used before. here chell reunites with glados, whom she places on her portal gun and carries with her.