There were really two choices: hide it or reveal it. The only way to hide it was to use a wish on Sarah's mind. Karyn was a little more reluctant to do that than she would have been in high school, and anyway she could always tell Sarah and wipe her mind later if need be.
"It's a magic stone," explained Karyn. "It belongs to Jon, and it grants wishes. But the wishes can never be reversed. I couldn't turn that TV back into the kind with a tube. And people remember the changes as if everything was always like that."
"Seriously?"
"You just got a nice TV set because of it, I think you can cut me some slack. We started out messing it up, I accidentally wished to have hair and breasts like yours."
"Uh-huh."
"No, seriously. You just remember it that way because the wishes change history and memories."
"And you never used your magic rock after that?"
"It's not mine, it's Jon's, and he wished to forget it until he was mature enough to use it. Some guy with a funny name held it until he was mature enough to deal with mistakes, which was close enough. Come on, Sarah, you have to believe me."
"I do, but... you know, when you hear about something like that you can't help but think about how it might affect you. Become rich. Bring your dead relatives back to life. Make college easy. You know, my parents are divorced. If I could just borrow that stone for a moment...."
"I can't, Sarah. We didn't talk about it much but I think Jon and I are going to go light on the mind control. You don't really want to bring your parents together by controlling their minds. And that's what you'll be doing. Anyway I ought to call Jon. He'll flip when he hears that I told you about the stone...."
