Primary School 27 looked like a huge red honeycomb from the outside - the bricks were arranged in hexagons and there was a clock hanging above the entrance that liked to be two minutes late. Inside, it smelled of freshly wiped floors, chalk and what the librarian called 'dust with history'. Maja knew that Mrs Kaczmarek's term was half-joking, but today it was meant to sound particularly serious. She had noticed it first just after she had handed in her permission slip for the trip to the open-air museum at the secretary's office. At the end of the north corridor, next to the cup display case, there was a narrow, dark grey door. Last week they had not been there. Maja could bet a whole packet of jelly beans on that. The door didn't have the school's scratchy paint, but a smooth, slightly shiny surface. A cool brass doorknob dangled from the side, and above it was a small plaque embossed with the letters: "12A". - Antek! - she hissed as her friend was just trying to pack a huge pencil case into a far too small backpack pocket. - See. Antek turned around, raised his eyebrows and immediately stopped fumbling with the zip. - 'They weren't here yesterday,' he said firmly. - 'Yesterday there was a cork board here with an announcement about a chess tournament. Nela! Come here, quickly! Nela ran over at a jog, clutching her sketchbook to her chest. She always carried it with her in case of an emergency to draw anything, even a hedgehog with a kilo of apples on its back. - Oh dear... - she whispered. - It's... a new door? To what? After all, the evacuation plan doesn't show them. The plan was hanging on the other side of the corridor, framed in a crooked green frame. Maja and Antek, almost simultaneously, ran up and pressed their noses to the glass. The rectangles of the classrooms were arranged like a jigsaw puzzle, the corridors drew straight lines and the stairs were marked with small black triangles. '12A' was nowhere to be seen. The empty space where the door now stood looked like a section of wall on the plan. - Maybe the local government had bought it? - Antek tried to be reasonable. - You know, some sort of student secretariat or something. - In a day's time? - Nela squirmed suspiciously. - And why hadn't anyone hung a notice? I don't think the Headmistress would install something in secret... well, in secret. Maja put her hand on the doorknob. It was as cold as a spoon taken straight out of the freezer. When she pressed it, nothing happened. It didn't move at all. - It's locked - she muttered. - 'We're going to see Mr Stefan. The caretaker, Mr Stefan, had hands always smelling of lemon liquid and pockets full of screws. They found him outside the gymnasium, where he was changing light bulbs. - Mr Stefan, and what is that door in the north corridor? - Antek asked straight out. - They weren't there yesterday. The caretaker scratched his baseball cap and squinted one eye. - A door like a door. I didn't install anything new there. Maybe for the chalk magazine? - He shrugged his shoulders. - Now I'm off to class, because I hear Mrs Kliś catches latecomers like... well... fish. Maja, Antek and Nela looked at each other in agreement. When Mr Stefan didn't know, it usually meant that he knew, but didn't want to say, or that there really was something very strange. That day the lessons passed more slowly than usual. In maths, the numbers were blurring before Majka's eyes, and in nature - although she liked to hear about insects - even the butterflies flying in the presentation seemed lethargic. During breaks, the three of them circulated around the north corridor, pretending to admire the cups. The door of '12A' stood silent and indifferent, as if it had been part of the building for a hundred years. It wasn't until after the fourth lesson that something happened that made the hairs on the back of Mai's neck rise as if from electricity. The bell rang at 7:19 a.m. Of course, it wasn't the right time, as it was almost eleven o'clock, but the sound was identical to that of the morning: metallic, a little snarling, as if the school had a throat of its own. It sounded once, briefly, and fell silent. A few first-graders giggled. The eighth-graders rolled their eyes. Mrs Kliś just sighed: - The installation is playing tricks again. Let's keep learning. Maja couldn't concentrate. She would have sworn that at the moment when the bell theoretically shouldn't be ringing, the handle in '12A' vibrated. Or maybe it was the light reflecting off the brass? Or had her head added a story to an ordinary thing again? She preferred to check. After lessons, instead of running straight home, they turned into the library. Mrs Kaczmarek arranged the books in such perfectly even piles that Maja was always afraid to sneeze. - Miss Kasia, do you have a plan of the school? The old one from before the renovation? - asked Nela, smiling that smile of hers which could soften the most stubborn adults. - I have all sorts of things - replied the librarian and disappeared behind a bookcase. She returned with a folder, from which a yellowed sheet slid out. - Please be careful. They spread it out on the table. The plan was hand-drawn, in ink. Maja ran her finger along the corridors. On the site of the current north wing was drawn something that might have been... an alcove? There was a strange parallel line, as if someone had wanted to mark something but had fumbled. - Here - whispered Maja. - But there is no signature. - Wait - Mrs Kaczmarek reached into her pocket and took out a thin envelope. - I found this once in an old atlas. A sheet with the 1979 bell schedule. Check it out. On the sheet, yellowed and soft like old tissue paper, the times of classes were written out. First bell - 7:19 a.m. Second bell - 8:05 a.m. Third bell - 8:50 a.m. The same ones that Class 5B's computer had displayed that morning for a while before it 'thought about it' and went back to normal numbers. - 'Interesting,' muttered Antek. - Today it also rang at 7:19... in the middle of the day. - 'Maybe it's a simple malfunction,' Mrs Kaczmarek shrugged her shoulders, but something like curiosity flashed in her eyes. - And you, dear children, have wonderfully expanded imaginations. And very well. Just don't wander in the corridors where you're not allowed. They promised they wouldn't. And then, as soon as they left the library, they looked at each other and all three of them knew that they would come early in the morning. They made an appointment for 7:05 a.m. The school was almost empty at that hour. The doorman was yawning and crossing a list of deliveries in his notebook. The light in the north corridor barely twinkled. The cold was biting into the palms of the hands, even though it was spring. - 'The plan is this,' Antek whispered. - 'We wait until the clock shows 7:19 a.m. If... if something happens, we watch first. We don't touch anything unnecessarily. - Sure - nodded Nela and took out her sketchbook. - I'll draw what I see. So that we don't get the details wrong. Maja took a deep breath. She had the impression that the corridor had lengthened by a few steps. "12A" stood in its place, but the plaque seemed to have dimmed. Or it was just the fault of the too early hour. They sat down on the bench opposite. Time was creeping along like a snail. Someone on the ground floor was dragging a mop cart, metal creaked against the threshold. From the music room came the single hum of a piano - probably the teacher was tuning the instrument for later choir rehearsals. At one point, Maja was sure she heard something else: a short, barely audible sound, like the sliding of a piece of paper over wood, but after a moment it fell silent. - 'Seven... eighteen,' whispered Antek, looking at the clock above the pedagogue's office. - Right away. The air became as if heavier. Maja felt a gentle gust, although the windows were closed. The handle '12A' flashed as if someone had wiped it inside with a soft cloth. The bell rang at exactly 7:19 a.m. Not the new, electronic one, but the old, metallic one, with an echo that, instead of rippling through the corridors, came back, as if waiting for its own reflection. At the same second, Maja heard a soft click - the sound of the lock moving inside. - Did you see? - Antek did not take his eyes off the handle. - It had moved! - Quiet - hissed Nela. - Someone... someone is there. A thin streak of light appeared under the door, like a strip of milky light, although there shouldn't have been any inside. Maja felt a tingling in her fingers, as if someone had covered them with sparkling snow. Everything went quiet until unnaturally so. The trolley, the piano or even the breathing of Mr Porter could no longer be heard. Just the three of them and that light. The doorknob vibrated once, a second time. The lock made a deafening, determined sound. The door swung open just enough for a narrow gap to appear between the frame and the doorframe. The smell of old papers and fresh paint wafted from inside, as if two different times had met in one room. - Maja... - whispered Nela, grabbing her by the sleeve. - Don't take a step. But Maja had already lifted her foot. Not because she wanted to ignore Antek's plan. Something like an invisible thread, as thin as the ones her grandmother used to tie packages with, pulled her forward. Not dragging, not rushing - it simply told her to stand closer. Behind the door something rustled. Softly, as if someone was moving a chair across the soft carpet. And then, just over the edge of the gap, a thin, bright line appeared - not of light, but of something shining like a silver thread. - Can you hear it? - Antek asked, almost silently. - It's... it's like... He didn't have time to finish. The doorknob dropped all the way and the door, silently like a page turning in a big book, swung open wider. Something flashed inside - the outline of tables, a row of chairs, or perhaps something else entirely - and then their name came from across the threshold. Clearly, cleanly, like the sound of a bell that doesn't go wrong. - Maya.