At six-three in the morning, Lena's phone vibrated as if a restless woodpecker lived inside. The e-journal notification glowed sharply in the dark room: "Change of plan. New classes: Building History. 6:40 p.m. Room: North." Lena lay on her back and stared at the ceiling for a moment, where the shadow of a plant from the windowsill rippled like a jellyfish. "Room North?" she muttered. At M. Copernicus High School there were halls from A to H, then the ones in the wing by the pool had numbers with the letter S, and in the oldest part - 1-33. North didn't fit into any of the systems, as if someone had given the name to the direction rather than the room. She wrote to Igor. "Do you have that too?" The answer came after a while: "This one. 18:40... Who gives lessons at this time? And what is that anyway?" "Probably an IT joke," Lena recalled how the school administrator, Mr Dzierżan, was able to insert yellow "Reminder to air the classrooms" boxes into the e-journal. But the joke didn't explain 'Room North'. Even before the sun contoured the roofs of the town, Lena stood up, opened the blinds and stood barefoot on the cool tiles. Across the street, the grocery shop was just lifting the metal blinds; at this hour, the world was flat and silent, as if someone had not yet started it up. At the school it felt the most. The Copernicus stood on a slight rise above the river, brick and serious, with glazed connectors like veins under the skin. At the front - a clock that had been preserved since the 1950s, which in no one's memory worked. It always indicated 11:17, even when the bells chimed in at half past eight. The corridors smelled of floor polish, chalk and what Lena called 'the spirit of the blackboard sponge'. She entered through a side door and already in the cloakroom Igor, with his hair in disarray and his inseparable hoodie, caught up with her. - 'I couldn't sleep,' he announced without greeting. - I called Kuba from 3D, he doesn't have it. I also checked with Hania from 2F - he doesn't have it either. Looks like it's just the two of us. - Why just us? - She asked. - Maybe it's a punishment for spilling phenolphthalein on the table in chemistry yesterday. Igor smiled crookedly. - 'Punishment is life,' he muttered. - 'But Mrs Karpowicz would have given you a rag and a reagent at most, not a class with a name like wind. Walking through the main corridor, they passed a display case with a trophy for the 1997 Maths Olympiad and an old photo of the class in uniform, most of whom had identical haircuts, as if they had been combed in one go. Hanging on the walls were posters saying "Good luck for the 2026 matriculation!" and an exchange announcement with a partner school in Finland. In the corner, under the winding staircase, sat the caretaker Spider, who was not called Spider, but everyone called him that because he had long fingers and a quiet, elusive way of moving. - 'Mrs Lena,' he said, as if she were at least a teacher. - What are you guys up to so early? - I wanted to... - she started, but Igor got into the word. - 'Mr Janie, is there any 'North Hall' on the schedule? - he asked. The usher squinted his eyes. For a moment he looked as if he was rearranging some shelves in his head. - 'There aren't any,' he finally replied. - 'At least in the normal sense. - And in the abnormal? - Lena didn't know where the question had come from, but the words slipped out like a ball out of her hand. The spider nodded towards the old wing, where the brick was warmer and the windows were narrow and high. - Sometimes someone says that for the north link. The one that is officially no longer there,' he said. - They bricked it up years ago. But kids like to give names. North. East. West. Sounds better than 'the one with the spiders'. - And 'the history of the building'? - pressed Igor. - 'History he has,' muttered the caretaker and shrugged his shoulders. - But classes at this hour? I haven't heard. Maybe some choir rehearsal? In any case, don't stick your noses where they don't ask you, or it'll blow. "It'll blow" sounded strange in the mouth of someone who usually spoke precisely and about practical things. Lena made a note of it in her head alongside everything else that was 'strange': the bricked-up link, the room that isn't there, the subject they didn't report. By midday, classes were going on as normal. In Polish, Mrs Bukowska had them interpret a poem in which water was a mirror and a language. In biology, Lena caught herself instead of looking at an onion slide under a microscope, following the movement of the hand of her watch, which she thought had twitched backwards once. At the break, Igor showed her a screenshot: "History of the building" was still on the schedule, typed only to the two of them, without the teacher's name, but with a footnote: "Attendance compulsory". - 'I checked the app logs,' he said in a whisper, as if in a library. - This is not an event added by the teacher. It shows up in the system as 'internal'. As if... as if it was done by the school itself. This sentence made the air in Lena's lungs grow colder. This is absurd, she thought. The building doesn't insert its own lessons into the timetable. And yet not everything at Copernicus was straightforward. Last year, she and Igor rummaged through the archives of the school newspaper and found a copy from the 1980s in which the students described a corridor that "you mustn't enter because you're coming back older". Everyone thought it was a joke. But at the time they didn't have notification of 'Room North'. After lessons, Lena and Igor sat on the steps by the music room, watching the building empty. The light was changing colour, getting sharper, as if the afternoon had drawn shadows from the wardrobes. The rustling of jackets came from the locker rooms, the shout of basketball practice from the court. Someone in the stairwell was tapping out chords on a guitar; the rumble was coming down the steps like a ball. - Shall we go? - asked Igor at 6:35 p.m. At that moment the old school radio station roared, the one that was rarely used because everything went through apps. A second later there was a voice that sounded through the long corridor. - Students assigned to the 'History of the Building' class are asked to report to Room North. Immediately. They exchanged glances and then stood up almost simultaneously. Their hands found their backpacks on their own. - 'If this is a joke, someone has made an effort,' Lena said, and there was more excitement than anxiety in her voice. They walked through the newer part, passing fluorescent plafonds, and stopped at a steel door separating the connecting passage to the old wing. A sign hung on the door saying 'Do not use - refurbishment'. The broken plastic swayed slightly, though there was no draught. Igor pressed the handle. The door gave way with a creak, as if it didn't like being woken up. The neck of the corridor led deeper, into a zone of different temperature. Here the smell changed to plaster and chalk dust. On the wall hung photographs of the classes: 1955, 1961, 1974. Leonid Brezhnev was looking out from somewhere from a banner, and next to him stood a boy with a crooked shirt and a sad look. Under one of the frames, someone had written in pencil: "We see you". The letters were faded but fresh in a strange way; Lena couldn't tell what it meant - as if it had been written yesterday and for fifty years at the same time. - 'Look,' whispered Igor. - An evacuation map. On the sketch of the floor, made with a thick line, where the connecting link now ended, another line was drawn, reaching further - to the north, as the arrow indicated. Instead of the room number, there was a small square with the letter 'P'. - Well - Lena swallowed her saliva. - Maybe it's just an old plan. Before they bricked up. It was cooler in the tunnel. The darkness had a milky tinge from the light coming in from somewhere above. At the end of the corridor you could see a brick - a wall that had been erected to cut off part of the building. On the left - the door to the utility room, padlocked shut. On the right - a narrow, high window showing a slice of sky where clouds rushed by like hurried horses. - How are we supposed to get to a room that isn't there? - muttered Igor, but he was already groping for the wall. - Sometimes they leave searches, bars, whatever. Lena put her ear to the brick. She heard something that could have been a vent... or a whisper. For a second she had the feeling that someone was calling her name from deep within, from many metres away. - Can you hear it? - She asked. Igor nodded, all too clearly. She moved her hand along the wall and came across a cooler section with a smooth texture. Plaster. Gently, with her fingernail, she pulled its edge. The piece fell away, revealing not brick underneath, but wood with an iron edge. - 'The door,' they said simultaneously, and for a moment it sounded like an incantation. The hinges were rusty, but they gave way. Before they entered, Lena looked over her shoulder. The corridor behind them seemed longer than when they walked in. Light ran across the floor like water. From the radio station (which, after all, they had left far away) there was a clatter and a furor, as if someone was rewinding a recording on a tape recorder. - Students... - the voice was the same as before, but now it sounded as if it was speaking from a very high ceiling. - Lena Ruszkiewicz. Igor Chmiel. You are late. The trunk of the door vibrated, as if something on the other side had taken in air. A light flashed in the crack - green, soft, like from a banker's lamp in an old library. Lena felt her heart shift into a faster gear. Igor pulled down his hood and reflexively smoothed his shirt, though it was grotesque at a time like this. - 'If this is a teachers' exhibition,' he whispered, 'they should have sold tickets. They pushed the door harder. The hinges groaned protractedly and the smell of chalk became intense. In front of them, where according to the plans there should be nothing but a wall, stretched a narrow corridor with wooden panelling, leading to a room with high windows. Showcases of memorabilia hung on the walls: an old journalistic typewriter, student ID cards from years ago, faded ribbons from banners. Light fanned across the ceiling, as if clouds were passing over it. Above the door to the hall, carved in brass, was the word: "Midnight". The door swung open of its own accord, rustle-free, inviting. On the blackboard - the real, green, heavy one - was whitewashed fresh writing: "6:40 p.m. Attendance compulsory". Below, as if someone had added in a hurry: "Latecomers". Lena felt the cold on the back of her neck. She glanced at Igor, who was silent, pale but with eyes kindled with curiosity. The quiet scraping of chalk came from inside the room, though no one was visible. And then, slowly, letter by letter, their names began to appear on the blackboard, as if an invisible hand was writing a list that no one could ignore anymore.