The Initial Target Stone: Zoe and Karyn Are Best Friends

In this new reality, Zoe and Karyn were both best friends. It was totally reasonable that best friends would be in the same bedroom, especially in the morning before school. (Karyn and Jon did the same thing quite a bit, before heading to school together.) But in this new reality, one of the two girls changed, so that it made sense that they were both close friends. Either Karyn had become a Goth girl or Zoe had become a tomboy. Which one was it?