The school looked particularly gloomy that day. The rain was tapping on the windows and the corridors were filled with the echo of muffled conversations. Ola adjusted her rucksack on her shoulder and looked at Antek, who had clearly been impatient for several minutes. - 'Tell me again,' she whispered, stopping at the corner. - How did you find this door? Antek glanced over his shoulder; he didn't want anyone to notice them. - Yesterday, after lessons. I was helping Grześ with his chemistry and wandered up to the third floor. That's when I saw it - a door without any markings, with the number 22 written in white chalk. Only... - he paused, lowering his voice even further - that handle was hot. Ola felt a shudder, even though it was only old school after all. They moved on, slipping on the slippery linoleum. At the end of the empty corridor there was indeed a door - old, dilapidated, incongruous with the rest. The lintel was covered in cobwebs, and underneath, barely visible, flashed the number '22'. Ola reached out, her fingers hesitating at the handle. - Maybe it was just a storage room? - A locker with a hot handle? Better check. They exchanged a brief glance and Antek pressed the door handle. Instead of the expected resistance, they felt the air around them begin to tremble, and a soft blue glow escaped from a crack at the threshold. The door opened silently. On the other side there was no dark technical room, just a wide, shimmering space, as if the entire air sheet was pulsating with energy. They took a step forward - the world changed in an instant. The floor was transformed into a mosaic of mirrors stretching all the way to the horizon, in which golden silhouettes flashed by. Above their heads, instead of the ceiling, a starry sky floated, even though it had been raining just a second ago. Ola looked into her reflection, but what she saw was not her face. It was older, more serious... and had completely different eyes. - Antek... - she whispered, and her voice echoed off the shiny walls. - Where... are we? From far away, somewhere on the border of their new world, there was a rhythmic sound like a heartbeat or... someone's footsteps getting closer. They had no idea what awaited them here.