You were Chell's younger sister, and accompanied her through all her adventure since the events of Portal. In your way to escape, you met Wheatley, a personality core who seemed to like you A LOT, and just took all the power from GLaDOS (and her body) after your "drain". He kicked out Chell and GLaDOS (who was now a potato), to the first Aperture installations Meanwhile, as you didn't get to be in the elevator at that moment, you just were left. With him. You were terrified of what would he do to you, since he had all the instruments to kill you, but he didn't. Instead, he just pet your head with a wire.

"Finally, it's just you and me, luv..."