In the attic of an old school, among ragged cobwebs, creaking boards and forgotten memorabilia, three friends - Lena, Maks and Tymek - were looking for secrets to uncover. It was a dark, stormy Saturday, and everyone had escaped the boredom and rain here. The attic had always circulated in school stories as a place where footsteps could be heard at night, even though no one went up there. Squeezing between cardboard boxes and old atlases, Lena finally stopped at something unusual. "Check this out!" - she whispered, pointing her finger at a huge, dusty mirror standing near the window. The frame was decorated with strange patterns and the glass was frosted, covered in a thin layer of dust. Maks pushed away the cobwebs and Tymek wiped the pane with his sleeve. For a moment they could only see their reflections, distorted by time and dirt. But then... something changed. Behind their backs, in the reflection of the mirror, a strange figure appeared - a tall silhouette, with a blurred face and long, thin fingers. Lena held her breath and Maks squinted. Tymek reached for the torch and directed the light at the mirror, but there was no one in the real world but them. The figure in the reflection, however, began to move, as if it was trying to speak to them, making disturbing gestures. Suddenly, the mirror trembled, as if someone was knocking from inside. A quiet metallic sound was heard - three short beats. The friends looked at each other in disbelief, and then an inscription appeared in the panel, as if scratched by a fingernail from the other side: "STAY." It became icy cold. Everyone froze, because just then they heard the floor creak behind them. Slowly, they turned around, ready to see what they feared most...