Copernicus High looks ordinary from the outside, but Kuba and his friends are pulled into a string of unsettling clues that lead them toward a locked room in the oldest wing.
Copernicus High rose behind its high concrete walls, grey and blunt against the pale spring sky. Kuba arrived early on his bike, as he usually did, and stopped by the gate with his phone in hand, waiting for Maja and, a little farther behind her, Igor, the newest and most unpredictable part of their little group. He liked these quiet minutes before the bell, when the building seemed half asleep and the corridors felt almost secret.
That morning, something in the air was wrong. Near the cloakroom, two younger girls stood frozen in the doorway, staring at something inside with wide, terrified eyes. Kuba slowed down. A cold draft brushed past him as soon as he stepped over the threshold, sharp enough to raise goosebumps on his arms. Every window was shut.
By his locker, he found Maja already waiting. She looked tense, her mouth set in a hard line, and she was clutching a folded piece of paper so tightly her fingers had gone white.
"What happened?" Kuba asked, lowering his voice.
Maja gave him the note. Her hand trembled once, then stilled. Kuba unfolded it and read: Not everything is what it seems. Look under your own feet.
"Please tell me this is a stupid prank," he said.
"I wish it were," Maja answered. "There were notes like this in several lockers this morning."
Igor found them a minute later, eyes bright instead of frightened, as if the whole thing had just been dropped into his lap as a challenge.
"Maybe someone wants to start a mystery before the exams," he said.
By the end of the first few lessons, the whole school was buzzing. People kept lowering their voices when teachers passed, and every scrape of a chair or draft through the hallway seemed to make everyone jump. Kuba tried to act normal, but the note kept burning in his pocket like it wanted to be found.
At lunch, the three of them slipped away toward the oldest wing of the school, the one students avoided unless they had to. Another note had appeared on the notice board there, but this one only showed a rough drawing: a door with a barred window and an arrow pointing toward the library.
Kuba stared at it. That part of the building had always felt off-limits, especially since the old janitor had once muttered about noises behind locked doors and never been willing to say more. Now the hallway seemed to stretch longer and darker than it should have.
When they reached the library door, it was already open a crack.
The room inside was dim and smelled of dust, paper, and something colder underneath. Rows of bookcases cast narrow shadows across the floor. Igor swallowed. "Now or never," he whispered.
Kuba pushed the door wider, and the three of them stepped inside together.
At the far end of the room, half-hidden between the shelves, stood a boy none of them had ever seen before. He was perfectly still, as if he had been waiting for them all along. Then he smiled and nodded them closer.