THE PLEAThe fever didn't leave me easily. It clung to me for three days, bringing strange dreams of cold hallways and the sound of heavy boots on stone. When I finally woke up for good, the sun was peeking over the edge of the canyon, hitting the camp with a soft, orange light.

I tried to sit up, and my head didn't feel like it was full of rocks anymore. That was a start.

"Look who’s back from the dead," Mara said. She was sitting nearby, sharpening a small knife against a flat stone. Scrape. ...