In Nadolce, autumn rolled in like a soft wave of fog: first it hid the bend in the river, then the roofs, before finally wrapping itself around the market square and the old town hall tower. Locals said that the great clock on the tower fell silent long ago when the last clockmaker passed away. By midday, the sound of bells no longer carried through the town, only the quiet creaking of shutters and the rustling of leaves. Hania was twelve years old, with a checkered notebook and a habit of remembering strange details. Olek carried a screwdriver in his pocket and a tiny torch he had converted himself from a bicycle lamp. Bruno could climb anywhere he wasn't supposed to, and always had something sweet in his rucksack for a rainy day. On a Friday a week ago, when the fog was so thick you could cut it, they heard something that had no right to happen. They were standing under the display of the former "U Gnomona" establishment, where clocks with broken hands slept behind dirty glass, and they were discussing a nature assignment. Then, instead of complaining about photosynthesis, they became immobile. From the depths of the tower - or from within the plant itself, difficult to resolve in this milky silence - a distinct bim... then another. Olek began to count reflexively on his fingers. There were thirteen. - 'It doesn't make sense,' whispered Hania, although she felt like saying it louder. - 'Or someone is making a joke,' muttered Bruno, but his eyes flashed with excitement. - Or... - Olek bit his lip. - Let's check next Friday. If there's a repeat, it's not a coincidence. All week, Hania had been writing in her notebook: "Friday, 19:07?" and put question marks next to it. She also sketched the market from memory, marking where the sound was strongest. Olek unbolted an old alarm clock dome, practising with his fingers and checking how the sound propagated through the metal casings. Bruno practised on the railing of the library stairs, for which he got a remark from the janitor lady. Another Friday arrived. Nadolce was once again shrouded in mist, and lanterns lit up like an amber eye here and there. The clock on the tower looked like a painting: motionless, with rusty hands that stuck suspended between twelve and one o'clock. An old cat squatted in front of 'U Gnomon', tucked its tail and yawned as if it knew all the secrets of the town. - 'The plan is simple,' said Hania, flipping through the pages. - First we listen. Then we check from the back. I made a sketch of the building. See, there's a narrow gate here, it leads into the courtyard. And here... - she tapped her pencil - there should be a workshop window. - Torch ready - Olek waved a tiny beam of light. - And a string, if you need to make a loop. - And I have toffee - Bruno added, pulling out a paper. - In case of a crisis. The clock - the still one on the tower - was silent, but the whole town seemed to be holding its breath. The air smelled of wet wood and iron that hadn't been greased with a single axle for years. Hania looked at her bracelet of thin string, as if it too could tell time. The hands of the watches on the phones jumped to 19:07. Nothing at first. Only the cat moved an ear. Then - as if from underground - there was a prolonged bim sound, clear as the sound of a tapped crystal glass. Olek nodded, counting in a whisper. Second, third, fourth. Hania made dots in her notebook, one beat - one dot. Tenth. Eleventh. Twelfth. The thirteenth pierced the fog like a needle. - 'Let's go,' said Hania, tucking her notebook away. - Now. They entered a narrow gate that creaked like a door in an old film. The courtyard was cramped, the bricks soaked with damp. On a rusty hook swung a faded sign with the half-smudged words 'Time Regulator - repairs'. At the end of the courtyard stood a wooden door with a small window. The brown paint was peeling off in patches. To the left, the microscopic warstat window was obscured by a curtain in which someone had poked a crescent-shaped hole. - 'It's closed,' Olek said, pressing the handle. The lock only rattled quietly. - Wait - Bruno crouched by the threshold. - Someone has lost something here. He pulled something metal, thin like a pointer, out from under the threshold. Indeed: it was a pointer, but with a thicker, ornately cut tip. On the head shone an engraved spiral mark, a little like a snail house and a little like a whirlpool on a river. - 'This looks like a key... but not to a regular lock,' said Olek, turning the metal in his fingers. - 'Look, that groove. Like it fits into a flat slot. - Or maybe for a clock? - Bruno pointed to the display on the other side of the glass. From the broken clocks looked the dials. One of them had a faded Roman notation of the hours. Hania squinted her eyes. - Wait. Can you see it? In the reflection in the glass there are... other numbers. There, in the mirror... - she pointed with her hand. In the dust mask, a clock from the exhibition standing opposite was reflected through the glass. In reality it had twelve digits, but in the reflection, in a certain corner, another one appeared, between XII and I, tiny, as if someone had added it with a thin pen. - Thirteen," whispered Olek. He moved the torch, changing the angle. Then Hania noticed something else: in the wooden frame of the door, right next to the handle, a hair-thin groove flashed in the light for a second, then disappeared. - 'There it is,' she said firmly. - A lock that only speaks to the light. Bruno, hold the torch. Olek, this pointer. A quiet sound came from outside, like the breathing of a great mechanism. Cogs? Imagination? Olek slid the metal "key" into a narrow slot. It fit like a glove. He moved it gently. Nothing. He moved again, slowly this time, in the rhythm he remembered from the beats: one, two, three.... - Look - Bruno leaned all the way over. On the wood, above their hands, a thin line began to creep like the hand of a clock, drawing an arc. The wood twitched, as if it were just a disguise for something hidden underneath. - It's a... panel. Sliding," Hania stated in a whisper. She slid her fingers into the emerging crack. A chill gushed from inside, the kind of chill that comes from basements where no one has turned on the light for years. On the opposite wall of the workshop, the outline of a heavy rack of boxes could be seen. One of the cardboard boxes rustled, as if a light draught had moved. Or... something else. - Do you hear that? - Olek asked. Somewhere behind the wall, deeper down, there were quiet tick-tocks, too regular to be a coincidence. But there were too many of them, as if every clock in the city had suddenly decided to resume its work under the floor of this one room. Hania reached into her rucksack and pulled out the thin gloves she had taken from the art room - they would come in handy if she needed to touch something delicate. She pulled the panel tighter. The boards gave way. She swung the opening wide enough for a cat to slip through, maybe even Bruno if he pulled his belly in. - 'I'll go first,' Bruno declared, without waiting for permission. - I am the narrowest. - Stop. First the light - Hania held him by the arm. Olek put the torch to the crack. The beam fell into the depths, bounced off something metal and returned, as if there, behind the wall, was a narrow space full of shining surfaces. Something shimmered. For a split second they saw a tiny brass plate with an engraving: the same spiral mark as on the 'key'. - 'This leads on,' said Hania, and her voice sounded more confident than she felt. She put her ear to the edge and listened. Tick... tick... tick. And then - something new. A gentle, barely audible creak, as if on the other side someone had pushed back another sliding mechanism. A breeze blew across the market, pushing the fog towards the courtyard. With a meow, the cat jumped off the windowsill and disappeared. Hania raised her hand and held her breath. Olek tightened his fingers on the 'key'. Bruno, hunched over, was preparing to slip in. And then, just when they thought everything had frozen, a single, clear thump came from the depths of the darkness - like the echo of a thirteenth bell, this time right next to their hands.