Portal 2 almost directly follows the events of Portal from Chell's perspective, although being set between 50 to 50,000 years after the events of Portal, which means it takes place between 2050 or 52009 CE. After awakening from a long cryogenic sleep, Chell finds herself in a decaying Aperture Science facility, where the once-dominant AI GLaDOS has been partially dismantled. As Chell navigates through the facility, she encounters new characters like Wheatley, a quirky personality core who helps her escape, and later becomes a central antagonist. The story delves into the history of Aperture Science, revealing the company's dark secrets through audio logs and environmental storytelling. The co-op portion of the game follows ATLAS and P-body, whom GLaDOS accompanies through the Cooperation Testing Initiative, offering a humorous and cooperative twist on the puzzle-solving gameplay.