The Retroactivator: Of Course it Was Sarah

"Well, you said this thing can make someone make a different decision on the past...but if you pick a decision an hour ago...that doesn't change much. But if you made a different decision further back...it would change other decisions." Zoe thought about it. "We need some kind of test. But on who?" Suddenly, the universe presented a candidate for her. Sarah McMillan...the worst bitch in the school. And Zoe could be pretty bitchy herself sometimes, but... She scanned Sarah from a distance. The device presented a list of decision points. "What are you going to do?" Zelda asked.