(Author's Note: I'm assuming that in her grandfather's letter it was supposed to say "I wish", instead of "I believe".)
Now, Athena was the best friend that Zoe ever had. Zoe trusted her and she trusted Zoe. Until now. She didn't think that Zoe keeping the talisman for herself was such a good idea. While, yes, Athena did make that stupid wish to make her hair blond and her breasts bigger, it was just an accident. And since Athena was better equipped when it came to things involving magic, she figured that the talisman would be in better hands if she had it.
So, late that night, she broke into Zoe's house when she was asleep and stole the talisman. She knew about her friend's stashing spot, so she knew just where to look.
The next morning, Zoe woke up to find her friend Athena standing in her room.
"Athena," Zoe said. "What are you doing here?"
She seemed embarrassed and was slow to respond. "I ... I had an accident."
"What kind of accident?"
Athena showed Zoe what the talisman had done to her.