"Schoolgirl missing", the ticker reads, and the camera cuts to a girl's face. Blonde hair waterfalling over her shoulders, serious eyes, lips a little parted like she's about to speak. That's when I realize I've been holding my breath, because the gasp when I inhale almost chokes me. Sadie Kelly has lost her job. Until last month, she was a teacher at Horton College - the same high school she went to ten years ago along with her best friend,...