"She's gone," Jon said, looking around.
"Who's gone?" Zoe asked.
"Karyn," he said, realizing that the front door was open. Karyn must have left!
"Who's Karyn?" Zoe shook her head. "Jon, pull yourself together. We have to find the stone."
"Stone? Hey, how do you know about that?" Jon asked, spinning towards her.
"You showed it to me, remember? I mean, I am your best friend. Who else would you show it to?" Zoe asked.
Now that Jon was really looking at her, he realized that Zoe was dressed very similarly to how Karyn dressed. Even her hair was short and tomboyish. And not only that, she seemed to be acting like Karyn as well.
And now thinking about what happened so far, Jon realized that the wand was somehow replacing people's personalities and lifestyles with the ones belonging to people nearby. Except for Jon, but that was probably because he was the one holding the wand. When he touched the wand to his mom, his mom took on the personality and lifestyle of Zoe, actually stealing it from his sister. And now, touching the wand to "zombie" Zoe, his sister took on the personality and lifestyle of Karyn, also stolen from Karyn. So now, Karyn was out there somewhere roaming around the neighborhood without a personality! He had to find her and try to get her back to normal, somehow.
"Hey, Jon-boy," Zoe said, acting chummy, the way Karyn usually did. "Are listening to me?"
"Huh?" Jon asked, breaking out of his thoughts.
"I said maybe I should try out the wand," Zoe said.