Jane Hopper walked through the crowded halls of her California high school with her backpack hanging from one shoulder. The bell had rung only a minute ago, but the hallways were already full of students laughing, talking, and rushing to their next classes. She kept her eyes on the floor. Groups of friends stood by the lockers, sharing jokes she couldn't hear. A girl showed her friends something on her phone, and they all burst out laughing. Two boys argued about basketball. Everywhere Jane looked, people seemed to belong somewhere. She didn't. As she passed a classroom window, she caught a glimpse of her reflection. Her brown hair hung around her shoulders, and her expression looked as tired as she felt. She quickly looked away.