(Apologies to Scott, too, but I just had to correct this...)
Jennifer looked over at her dresser, where the stone was sitting, and suddenly realized something. She reached for her cell phone and dialed up Liz. There was no response after several rings, and she nearly yelled at it. "C'mon, Liz, answer!"
Liz finally picked up the phone. "Hello? Jen, it's you, isn't it?"
"Yes, it's me!" said Jennifer. "You've got to get out of there. Look, where are you right now? And do you have the stone?"
"I didn't break in yet. I'm a block away from Jon's house, near a bus stop.
"Stay there. Or go home. The whole thing's a trap!"
"A trap?"
"Yes. I have the stone. Look, when I go back in time and become Jen, the stone comes with me. Remember the first time?"
"Yeah, Jon put you on the speakerphone so that Karyn and me could hear you."
"Well, that time the stone was right there on my dresser, same place it is now. When Jon went back and became me, the stone went along. It was in two places at once, just like I'm really in two places at once. But I bet that even though I don't need to touch it for it to come with me, I still have to have it. If you steal the stone now, Jon won't have it--so I won't have it--so you'll have changed the past. And another thing, Liz. You and Karyn were there. You heard me talk on the speakerphone--you both heard the entire story about me going back in time. But today Karyn acted as if she hadn't ever heard it."
"Do you think she's really Karyn?" said Liz.
"I don't know. She could be an impostor. Or she could be under someone's control."
"Jen," said Liz, "maybe you're under someone's control."
"Don't be silly."
"Take the stone and wish that you're free of any compulsions and suggestions. If you haven't been affected, it shouldn't hurt, right?"
"Um, okay, Liz, but I still think that's silly." She lay her palm on the stone and said "I wish to be free from any magical or drug-induced compulsions and suggestions." Then she yelped.
"Jen, what's wrong?" said Liz.
"It's Jon. I hated Jon, for some reason, until I made that wish."
"You can't hate Jon. You are Jon as a girl!"
"Yeah, Liz, but there was something.... I don't know what. Though it's not the stone doing it, or I wouldn't have been able to reverse it. You know, Liz, I wish you were here with me and that my parents wouldn't notice."
Liz suddenly materialized in the middle of the room. "You know, Jen," she said, "I'll never get used to that."
"We've got to think," said Jen. "Who could have done this? Bryan? Sarah?"
"Why would Sarah do that? Maybe it was someone who hates Jon, and gave me some kind of suggestion to hate Jon too. They wouldn't have to know about me and Jon because they'd just give me the suggestion and I'd subconsciously come up with the trap myself."
"And Karyn?"
"Either that wasn't Karyn, or else Karyn was so under someone's control that she didn't have her own memories. But we've got to think of something. We need to find out who's doing this, and how, and soon...."