Sarah Isn't Sarah

"Sarah?" Jon asked. It felt strange hearing Biff's voice instead of his own. She looked at him and said "Sarah? My name isn't Sarah." She looked around. "Where am I? How did I get here?" She grabbed her neck. "And what happened to my voice?" She looked around some more, but then stopped when she saw herself in the bedroom mirror. She then sat up and crawled to the edge of the bed, all the while staring at her reflection with disbelief. "What happened to my body?" It was obvious now that Jon wasn't the only person who woke up in someone else's body. Sarah was no longer Sarah. So who was she? "Who are you?" Jon asked. The person who now had Sarah's body turned and said ...