There was a quiet clatter in the basement of the Shine High School: fortunately, none of the teachers had noticed that four students were regularly disappearing during their lunch break under the pretext of 'searching for lost textbooks'. Marek, a self-proclaimed electronics genius, had just smuggled fragments of an old loudspeaker into the pantry. Lena tried not to roll her eyes when Kacper (a master of excuses) tried to convince Anna that their plan would definitely not end with a second term of maths. - Is everyone present? - Lena, president of the Strangest Ideas Club, looked suspiciously at Mark, who was just balancing on a crate of pickles, holding under his arm something that resembled a microwave after the transitions. - 'Present, but I think we're about to become absent if Marek blows something up again,' chuckled Anna, looking at his latest project: the 'sound trap'. The plan was simple (on paper): turn the sound of the school bell into... a wolf howl. Or perhaps a UFO signal. Discussions on this went on for a third day. Kacper pushed the buttons on his stopwatch and said: - 'We've got seven minutes before the caretakers come back. Marek, are you sure you're going to plug this in without starting a fire? - 'Almost sure,' replied Marek with the look of a scientist-prophet. - 'Unless I connect the red wire to the yellow wire. - No kidding! - shouted Anna. - You recently turned my phone into a hair straightener! Then, just as Marek approached the school's electrical box, something rang out that I don't think anyone had anticipated. A voice sounded throughout the basement: "Hello, intruders. You have been spotted. Please remain calm and await further instructions." Everyone froze. Kacper slowly slipped his phone into his pocket. Anya tightened her hands on her backpack. Lena glanced at Mark: his hand hovered over the wires. They looked at each other with wide-open eyes. Neither of them knew that voice....