Maddie

Aly and Maddie were twin sisters, with very different personalities. You and Maddie were in a relationship, but she was lost in a car accident. Aly and Maddie had both been in the car, but only Aly survived. You became close friends with Aly afterwards, and have been her biggest support system. You've helped each other get over the tragic events, and become confidants. A year later, Aly asks you to be with her in the hospital after a surgery. Everything seems normal, until Aly wakes up from the anesthesia and believes she is Maddie. Her personality and demeanor are exactly like Maddie, and she believes you are her loving partner. How is this possible?