Fog stood over Kazimierz like the heavy breath of a river, hanging between the rooftops and street lamps on Józefa Street. From afar came the whispering sound of a tram, as if someone was moving a spoon over porcelain. At the gate at number 17, the tenement picked up the echo of footsteps and reluctantly returned them to the well's courtyard. Lena stopped for a moment under a sign: "Clockmaker. Jozef Glowacki. Since 1962." The faded letters stuck together with air as damp as a blanket. Today's key - the one she had received from her grandfather - was heavier than usual. Brass, with the number 13 engraved on the blade. The metal clung coolly to her hand as she slid it into the lock. A sense of strangeness and closeness at the same moment: as if someone was opening a drawer in her memory. Inside, there was the smell of paraffin, old wood and mechanism oil. There were clocks hanging on the walls: pendulum clocks, floor clocks, puppet clocks, even one with a skeleton that moved its eye sockets instead of hands. They were all silent. Lena closed the door from the inside, slid the bolt in and for a moment just stood there, listening to this silence, which said more than the ticking. She had spent the last few weeks sorting through papers. Billsheets, old orders, slips of paper with quiet requests from clients: "Mr Joseph, speed up my time by a week, I can't make it for weddings". She smiled then and put the card away. But today she took something from the bottom shelf that she had been putting away since day one - a thick leather-bound accounting notebook with rubbed corners. Not for bills. These were notes. Her grandfather wrote in small letters, strictly, as if he was avoiding blanks, meticulously writing down not only repairs but also things not ordered in the workshop. "1 November. Fog. The choir from the tower falls silent after six bars. 2:13 - clink of glass behind the wall. 3 November. The voice pipe whispered to itself. 0:57 - don't turn away the mirrors'. As Lena ran her finger along the lines, she felt her own pulse trying to tune in to these records. In the margins, her grandfather had drawn microscopic sketches: fragments of mechanisms, diagrams of pipes, a plan of the courtyard with a cross marked in a place that was not on any of the maps. And next to one of the drawings, pressed like a bookmark, she found something else: a small, thin key with a blue streak of enamel. A mark was carved on the head of the key: a semicircle based on three dots. Not greedy, not claiming. It looked like a toy heirloom, yet the weight was definite. On the counter stood a regulator - a clock that Grandpa trusted more than his own watch. A narrow brass plaque was affixed to its frame: "Do not set after meals". When Lena set it straight and touched the pendulum, the metal vibrated like a string. The quiet tick lengthened to a quieter yes. The movement began to draw in the entire space, arranging it into linear sections with each second having a bench. As the hands measuring the authentic, communal, urban hour set to midnight, someone knocked on the door of this silence. A tap-tap, a quick, nervous rhythm. Lena jumped up and headed for the entrance. - Miss Lena? - she recognised the voice of the neighbour on the first floor. Mr Oskar always wore a cap, even at home; his eyes were as dull as stones in the Vistula riverbed. - I wouldn't stay alone with all these clocks, not today. Today it's like.... - waved his hand - bounce. - Bounce? - Sound. Tenements can pass on more than they give. Your grandfather knew. He had his ways. But what am I going to do... - he sucked in air, as if he had forgotten where a sentence begins and ends. - If anything happens, I'll leave the light on the cage until morning. - Thank you, Mr Oskar. - Lena smiled, although inside she felt a slight sting, like a pin in a pillow. - I'll let you know if... anything. - If anything - he put his finger to the visor of his cap. - Please don't look in the mirrors. Your grandfather always turned them over at night. When his footsteps fell silent, Lena turned the mirror standing on the back shelf so that it reflected only the darkness. Was it superstition or method? In her notebook she found another clue: "If 13 comes, don't stand in front of the door". Next to it a number calligraphed on half a page, ordinary and yet intrusive. In Krakow's towers, the bells ring evenly, and the extra tone is no longer a clockmaker's joke. It's like a letter that goes to only one addressee. Lena set up a chair next to the cooker, where the embers held only the smell, not the heat. On the table she placed a notebook, a blue key and an old torch with worn glass. The walls were moving, not because they moved, but because the ticking opened invisible gaps between them. All the clocks in the workshop remained off, except the regulator. And except for one she had forgotten about - the little alarm clock in the shop window, a dormant mechanism that had just breathed for the first time in years. A whisper came from behind the wall, so subtle it could have been the movement of plaster. Lena stood up and looked at the back wall, behind which once housed the parts cupboard. She had parted with it moments after the funeral; it had been sold because someone had offered an obscene price for the worn wood. All that remained was the outline on the wall, a rectangle a tone lighter. Now, in its bottom left corner, she matured a round, almost invisible cap. Diameter: maybe two pennies. In the centre - the microscopic outline of a semicircle on three dots. The steps leading to the back room squeaked as Lena reached for the blue key. She didn't want to rush. Nevertheless, the movement of her fingers was quicker than thought, as if her body remembered someone else's habit. The key slid into the hole without resistance. The metal was cold, but when she turned it, something similar to electricity passed through her skin - not painful. More like an understanding on the tongue. There was a crunching crack of old mortar from the side left by the wardrobe. Lena snorted a laugh that came out too sharply to be evidence of courage. She reached for a torch and illuminated the outline. The plaster didn't crack; it spread, slowly, the way lips crack before they say a word. Air gushed from the dark opening. Not stale, not cold. Rather, the kind that had long ago left someone's lungs and now reminded them of them. The regulator on the counter went into a brief tremor, the pendulum punched a hint of uneven time and then settled back. Outside, some cat jumped off the canopy, a grain of plaster sprinkled. Lena slid her hand into the rectangular hole and felt the metal edge - the guide. She pushed. The panel moved inwards the width of the book and stood up, as if waiting for the next signal. She had once come across a story about a whispering pipeline that ran through tenements like an extra nerve of the city before the war. The pipes were supposed to connect flats, gatehouses and, supposedly, even bell towers. My grandfather once recalled in passing: "We have more sewers here than water pipes". Inside, in the blackness, Lena recognised the smooth, matt surface of the pipe, diverging at an angle somewhat unnatural for a building of these years. She leaned her ear in. After a long cloud of silence, she heard something that was not a sound. More a way of silence existing. As if the silence had clothes and was just straightening them. The minute hand came up to twelve. No bell, no announcement. Midnight came like someone who knows the way and needs no applause. Maybe it was the fog that dampened the towers, maybe it was the city that forgot to breathe for a while. Lena felt a chill creep into the back of her neck, even though the cooker gave off residual heat. A narrow cone of light spilled from the torch, hitting straight on something that looked like a number. Inside, just at the edge of the tube, someone had scribbled finely: 00:59. Next to it, a down arrow. Still next to it - dashes, like hands spread out on a tabletop, only without a centre. Lena checked the regulator: 00:58 - one minute. Instead of fear, she felt a peculiar gratitude that someone had left her a sign. She thought her grandfather had planned this moment not for himself. The notes spoke of this time; they also said: 'If you hear the thirteenth tone, don't turn around too quickly'. In the margin: "Hide the mirrors". She took her phone out of her pocket and flipped the screen to the tabletop so it wouldn't glow. Behind her back the upturned mirror was catching the breath of the workshop and nothing else. In the back room it began to drip - maybe a tap, maybe a pipe, maybe something in the humid air like counting to infinity. Lena rested her palms against the worktop, feeling under her fingers the sprouts from hundreds of screws and bolts. This was where her grandfather's fingers must have stayed the most - it's strange how old touches can survive on surfaces. 00:59 Something in the pipe sighed. It wasn't a breeze, more a kind of heavy, metallic semitone movement; as if a mechanism that isn't a clock has decided to cast a shadow over the human world. The first sound came from the street. Or from the tower. Or from an unidentified place in between. Single, clear, sustained. The second, a tad lower, as if a stone had shifted a hair's breadth in the wall and the oak tree had sung a counter to it. Then a third, a fourth, a fifth. Lena counted in her mind, matching her breath to the rhythm and her hands to the trunk of the table, despite herself. Tenth. Eleventh. Twelfth. The anticipation stretched and broke like a thin thread. And then, from the depths of the tube, a tone rang out that could not be compared to anything from the city. It wasn't loud, it wasn't even fully audible. It was more present. The hands in several of the clocks that had been switched off trembled. In the corner, on a shelf, a fly stopped, too sluggish to carry its own weight. The key in the hole moved itself a millimetre. The panel vibrated. And the wall, the one with the outline of a non-existent wardrobe, did something more befitting a chest: it drew in air. The top left corner of the panel bounced back a hair and fell into shadow. A dry sound came from inside, as if someone was turning a second, larger key at exactly the same time as she did. Reflexively, Lena raised her torch and the cone of light cut through the dense haze of dust and stopped on a line that began to gradually glow a cool green. Fine diodes? Phosphorescent paint? The pattern resembled a diagram of some kind of circuit - a semicircle, three points, and underneath them a series of dashes that suddenly....