She is aided in her adventure by the personable floating robot Wheatley, while the villainous AI GLaDOS continues to torment her. As the building threatens to collapse, Chell must find a way to escape by using her trusty portal gun. After narrowly escaping the Aperture Science research facility in the original Portal, Chell finds herself trapped once again within its now crumbling walls. In the single-player mode of Portal 2, players once again step into the shoes of Chell, an unlucky test subject who continuously finds herself trapped and at the mercy of plotting machines.
