Callie MY EYES SNAPPED OPEN when I heard the humming. I raised my head. It was still early, but I was already lying on my mattress, trying to sleep. Of course, there was little chance of that actually happening. Every time I started to drop off, imaginary lines of magic lit up in my head. I’d sit up to follow them, and they’d blink out, leaving me in darkness. But the humming was something new. I scrambled to my feet, rushing out into the corridor. The discordant sounds seemed to come from everywhere, impossible to follow. I closed my eyes, listening to the notes. They sounded familiar, some vibration my body knew but couldn’t name. I let myself respond to them, humming too under my breath. I turned, almost without realising I was doing it. A line of fireflies lit up. I waited, but

