The rain had the taste of metal that evening, as if the city had put a coin in its mouth and sucked it insistently. Lena walked briskly along the granite wall of the former station, clutching a heavy brass key in her coat pocket. The key had nothing to do with the door to the flat or the safe; it was too old, too ostentatiously different. On its head, beneath the old patina, shone an engraved line: 00:13. Her grandmother's letter smelled of old lavender and dust. She found it in her recipe book, between the apple pie and the duck and apples. A couple of neat sentences in the bullet-pointed handwriting used to write things too important to make a mistake: "Lena, if you're reading this, it means you're ready. The tower has preserved everything. Go when the mist settles over the river. Set the clock for thirteen o'clock at midnight. Don't be afraid of the sound, it will be different from all the others. Remember the key. Marek will help you." Marek was already waiting, leaning against the doorframe of the side entrance. A clockmaker to whom time didn't leave too many marks on his face, he loved oil stains on his hands for that. He was always a little too early and a little too close to the heart of all the world's machinery. - Have you got it? - He asked without greeting. Lena nodded, taking out the key. The metal was as cool as a mirror. They approached a steel door on which the names of the former railway authorities were written in faded letters, worn down to the point of legibility. Marek put out his torch and shone it on a niche so small it could be mistaken for a defect in the wall. It was there, in a dark recess next to the hinge, that the lock waited - a narrow slit of an almost whimsical shape, as if it had been worked on by someone in a hurry, with thought only at the end. The key entered with resistance, the skin on Lena's fingers tightened as she turned it slowly. The mechanism responded with a deafening sigh. The door didn't even make a squeak - it opened softly, as if the air sat behind it, waiting all its life for that one quiet movement. The tower greeted them with the smell of rust, tar and decayed boards. The narrow staircase climbed in a spiral, so close that my shoulder rubbed against the wall. Marek went first and Lena counted the steps, as she always did when she was afraid of silence. On the mezzanine floor they passed a display case covered with oilcloth; under the thick film they could see metal gears, a box with moss-grown screws, a plaque with the inscription: "Design: Heliodor Zaleski 1908 - Transitional Chronometer". - 'Zaleski,' said Marek, pausing, as if the name alone could change the weight of the air. - He was whispered about. He disappeared from the papers, and his project disappeared from memory. Only this place remained. - Just that and the grandmother's letter,' Lena replied. - Too much detail for a legend. At the top of the stairs a square room opened up under the roof, where a huge cogwheel stood as still as the moon on a windless night. The skeleton of the clock glimmered in the semi-darkness, each axle and each needle had its place in the mountains of dust settled over the years. Opposite, behind the dirty windows, the city stretched out: the river like a dark lane, bridges like embroidery, car lights slow as skylights. Above it all hung a grey mist, soft and endless. A hardcover notebook lay on the table by the window. Lena rubbed the burned edge with her finger and opened it carefully. Inside - drawings of mechanisms, drawn with a determined hand, next to words, some of which had been eaten away by time: "outfit ... do chw...", "ampl... pendulu...", "przesu... in the experiential sphere - only in the perim... tower". A photograph is pasted between the words: a blurry patch of people in dark coats, standing on a platform. On the back in crayon: "Before - 21.10.1909". - See - Marek pointed to the panel next to the main wheel. - A key slot. The second one... it looks like a cassette for sound recording. As if you need to feed the machine with the breath of time. - Or a signal,' Lena added, feeling a strange tightening in her stomach. - 'The grandmother wrote that "the sound will be different from all the others". The main face of the tower clock on the other side of the walls was silent, but here, at the heart of the mechanism, a dormant rhythm was simmering. Lena slid the key into the other socket. It fitted as if it had always been here. Marek, bent over an old Bakelite cassette, unwound a thin tape from the string - a recording that someone had left like bread on the windowsill for an unexpected visitor. - Let's see what they left behind,' he muttered, and slid the tape in. - Maybe just what is not allowed to be played at night. Lena laughed briefly, nervously. - You know how at times like this a person regrets not carrying talismans with them? - She took a deep breath. - I set it. Thirteen o'clock at midnight. The hands moved with resistance, as if someone were dragging them through thick honey. When the big long one touched the vertical and the shorter one caught up with it at the bottom, something in the room vibrated. The air hardened. High above their heads, in the wooden ribs of the roof, it rustled as if a river had flowed through the beams. - Shall we take off? - Marek asked, putting his hand on the cassette switch. Lena nodded. - 'Before I think about it. Click. At first there was just a hum, grainy like snow on an old TV. Then two sounds emerged: the distant whistle of a locomotive - so distinctive as to be unbelievable - and a beat, not like a clock, but like a heartbeat. Weak, uneven, as if someone had recorded the pulse of the city and put it back together in a black box. The clock answered. The pendulum, which had hitherto been motionless, swung with the sluggishness of a sleeping colossus and began to swing in the opposite direction than it should. The lights outside the window dimmed. The fog lit up from within, as if someone had blown warm air into it. On the photograph from the platform, which Lena had not even had time to put down, patches of thicker shadow began to appear, darkening into shapes: hats, suitcases, hands. According to the date her grandmother had added, it was supposed to be "Before". And now the photograph looked as if it wanted to remember what was "After". - Can you feel it? - Marek whispered, although there was no reason for it. - The smell. The smoke from the coal. I... something earthy. Lena could feel it. It was as if someone had taken the skin off her memory and exposed a completely different nerve: primitive, primal, flashing in the lights that were no longer there. Suddenly, a drop of water - not rain, not condensation, just water with the warm smell of soap and grease - fell from the upper window slat. It fell on Zaleski's notebook and left a wet dot on the word "transfer...". The tape in the tape recorder beeped; for a second, a different sound rang out in the speaker, human, drawn by age and kilometres, and yet strikingly close. - 'Lena, don't be late this time,' said the voice. Marek twitched. - Who...? - The grandmother - she whispered, although she wasn't sure herself. - Or... She did not finish. The mechanism deep inside the wall, hitherto as inert as a statue, began to breathe. The gas pedal - because that's what Marek called it for a joke - moved a little bit on its own. The numbers appeared on the panel: 00:12:57. Three seconds into the truism of the night. - 'It's not just running,' Marek muttered, with a seriousness she'd never seen from him. - They were powering this with more than just electricity. Sound, movement, intention. We have to decide, Lena. Do we go into it now. Lena looked out over the city. A milky river of mist moved over the rooftops, white and thick like a thought that cannot be spoken. On the far bridge stood a train that wasn't there; she could see a carriage in the painting of a hundred years ago, with people in coats, like in a photograph. And across its glass, parallel, moved a bus from the present, leaving side by side for a second two shadows on one and the same water. - Why me? - she asked, not knowing herself whether she was talking to Mark, to her grandmother, to Zaleski or to the city. - Because someone left you a key,' Marek replied. - And because you are able not to run away when the world starts to happen. The digits jumped: 00:12:59. 00:13:00. The clock struck. Once. Then a second, a third. Its sound was lower than it should have been, more corporeal, like drops hitting wood, like the clatter of knuckles against a table. The thirteenth time didn't sound alien. It sounded like what had always been there, only no one dared to name it. At the same time, a vertical strip slid out in the wall next to the panel that didn't resemble a door - just a line of reality that no longer agreed with itself. Light poured through the gap. - 'That's it,' said Marek, grabbing Lena's wrist, not to stop her, but to make her feel like she really was. - 'Remember. We're coming back if... if... - If we have something to go back to,' she finished, and surprised herself at how calm it sounded. Beyond the gap there was no darkness. There was a platform - familiar and alien at the same time. The same station, the same brick arches, and yet smelling different, differently chewed up by the wind. Steel lamps with milky shades dangled from the ceiling, lit by a warm yellow light. To the left stood a bench on which someone had left a newspaper; the date could be read even from here: 21 October 1909. At the edge of the platform, where the perilous blue of the tracks begins, stood a woman in a sepia coat, with a tie knotted like that of a turn-of-the-century student. She had Lena's eyes, only differently penetrating. She raised her hand. Lena felt the ground beneath her - this present, with its smell of damp and oil - become lighter for a second. The light from the crack moved across her shoes. A long, low whistle call rang in her head - the kind you can't hear unless you remember it from a childhood you never had. - Now? - Marek asked a question that was more breath than word. - 'Now,' Lena replied, putting her foot on the threshold, at the precise moment when the second hand on the tower dial - the only one they had never seen before - split in two and went in opposite directions, and the air between times tightened like a thin, vibrating membrane....