The attic of the old school on Maple Street was full of dust, cobwebs and things long forgotten. It was there, one afternoon, that Sonia, Michal, Lena and Igor - four friends who love adventure - met. Sonia was the first to notice an old, huge mirror leaning against the wall between a rusty globe and a box full of strange musical instruments. It had a golden frame and the surface was dull and hazy, as if it reflected not the world but someone's dreams. - 'Oi, look at that! - exclaimed Sonia, running her hand over the glass. Suddenly it seemed as if her fingers disappeared inside the mirror. The boys and Lena ran closer, disbelieving their eyes. - This must be some old trick, maybe a door? - Igor carefully moved his finger across the sheet. And then something squeaked. A moment later, the mirror flashed with blue light, and a swirl of turbulent colours appeared in the centre. - Are we going in? - Lena asked in a whisper, holding Sonia by the sleeve. Without waiting for an answer, Michael took the first step. Suddenly, he disappeared. Before the others had time to think, they were drawn in behind him. They penetrated the glass as if it were water, and the world swirled around them, until suddenly.... They were standing at the edge of a forest. But this was no ordinary forest - the trees had silver leaves, and their trunks shone like mirrors. Everything was reflected in them a thousand times: every twitch, every movement of their friends. As they moved ahead, they realised that the ground beneath their feet reflected their faces like the surface of a lake. - 'I don't think this is our school,' Lena remarked, looking around uncertainly. Suddenly there was a sound from inside the forest - quiet, as if someone was playing a glass harp. Luminous streaks reflected off the trees and danced through the air, guiding them like skylights. - 'I think someone is waiting for us,' whispered Igor. The friends followed the luminous path, and their reflections in the mirrored trees began to behave strangely - one of the boys noticed that his own reflection blinked at him and moved in a different direction from himself. They stopped right in front of a large, shining tree in the middle of the clearing. Face-like shapes could be seen in its bark, and the branches bent as if inviting them in....