Tuesdays at our school are like socks that don't match: they seem to fit, they don't fit. My name is Mika, I'm fourteen, and I have an illegal licence for trouble. Tymek and I operate the Found Goods Cupboard, a monster in the basement of the school. Mr Wrzos says it's volunteering, and I say: economic heroism training. Officially it's Primary School Number Seven, unofficially: a base for experimental canteen smells. Today someone dropped off a metal breakfast box that purred through the closed latch. A sign on the lid read: Don't open if you like regular Tuesdays, seriously. My brain sent out a warning, and curiosity responded with an automatic click of the latch. From inside gushed the smell of fried onions, a fan, and a piece of paper with the caption: Instructions. Inside, something clinked like coins, then sighed, as if it had lungs. The instructions sounded like they were written by a very nervous toaster after three sugar-free coffees. Point One: Don't panic unless you hear laughter coming from the tutor's backpack. Point two: If a flickering dot appears, act naturally and breathe like an actor. The flickering dot appeared immediately, perched on my nose and made raised eyebrows. I tried to blow it off, but it began to tickle and display miniature breathing instructions. We glanced at each other and Tim whispered that I looked like a mosquito lantern. The dot moved sideways, leaving a thin, luminous streak, like a very ambitious slug. The streak led to the attic of the school, to a door with a sign: No Entry, Rebuses Work. The lock made a sound like a cat's keyboard, although no one had even touched it. The corridor was empty, with only the security board practising yoga with the reflections of fluorescent lights. Each step creaked so dramatically that Tymek offered end credits to pass. The box in my hands whirred, tapped out a ringing rhythm and then blinked green. The card added a sudden point three: Open if you want to meet the author of the school pranks. On the other side of the door someone sneezed three times, followed by a very meaningful silence. I reached for the doorknob when suddenly a dot spelled out a single word on the air: Run away.