"I wish me and Zoe were back in our bodies," Sarah said.
The stone then glowed, granting her wish.
Sarah looked down at herself, expecting to see her body, but instead, she still saw Zoe's. "What the hell? I'm still in your body."
"And I'm in yours," she heard her original voice say. Sarah looked towards the source of the voice and saw her body standing a few feet away, wearing the clothes she was wearing when she came to Jon's house.
"Zoe?" Sarah asked, still with Zoe's voice.
"Yeah, I'm in your body," Zoe said, with Sarah's voice. "Ugh. I can't believe I look just like you."
"This isn't what I wished for."
What Sarah failed to realize was that thanks to her previous wish of "I wish that I looked exactly like Jon's sister Zoe right now," she could never look like anything other than Zoe. So her wish for both herself and Zoe to be back in their bodies kept Sarah in Zoe's body, but then put Zoe in Sarah's, which came back. The stone won't allow Sarah to look like anyone else ... just Zoe.
