Fog crept along the pavements like spilt milk, and the sound of bells from bells attached to costumes mingled with children's laughter. Sunny Street was full of pumpkin lanterns that evening, flashing cut-out eyes and smiles. However, there was semi-darkness at the end, where the number 13 had been haunted by a scratched sign for years. - Are you sure this is the house? - whispered Lena, adjusting her bat-eared headband. Her cloak rustled as she stood on tiptoe to see better through the iron gate. - 'The map can't be wrong,' said Olek, pushing his hands deeper into the sleeves of his silver astronaut suit. - Besides... today is Halloween. If not now, when? Maya, wearing a hat with a crooked brim and a dress sprinkled with glitter, pressed a thin library book to her chest. Still in the morning, she found dried maple leaves between the yellowed pages and a page with a few lines that, at first glance, looked like scribbles. It wasn't until she lit a pumpkin lantern in the house that the lines began to glow a pale green, forming a street plan. On the map there was a circle by the number 13 and notations: "Knock when time runs backwards" and a tiny drawing of a bell and a leaf. - See - Maja lifted the book. - As we get closer, the letters get brighter. It's as if... the lamps from that window are feeding them. In the window of the villa at 13 Sloneczna Street, among the curtains completely still despite the gusts of wind, stood a pumpkin lantern. Its flame was not ordinary. It glowed greenishly and occasionally splashed sparks that arranged themselves into shapes of leaves and dots. Above the door hung a brass bell decorated with maple relief. The gate squeaked as Olek pushed it open gently. Surprisingly, it was not locked. - 'A popular place for 'trick or treat',' Olek muttered, feigning courage. - I'll go first. - You must be crazy - snorted Lena, but she was already taking a step behind him. Maja struggled to tear her gaze away from the map, which pulsed as if alive. The garden on the other side of the gate looked as if it had stopped in time. The grass was tall but evenly laid out, as if someone had combed it every day. Wooden apple crates stood between the currant bushes, and dry vine shoots hung from the pergola, tangling like ropes. A quiet knocking sound came from inside the house - as if someone was moving the pawns on a huge chessboard. - Do you hear that? - Maja stopped, messing with her head. - The clock. Behind the frosted glass of the door, the jagged shadow of a pendulum could be seen. The ticking clearly sounded backwards: tic-tac-toe arranged in yes-tic, as if someone was playing the recording backwards. The skin on the nape of Lena's neck turned ruddy, but she did not take a step back. - 'Knock when time runs backwards,' Olek repeated in a half-hearted voice, grabbing the brass leaf-shaped knocker. - 'Well, I think it's just now. The knocker hit the door three times, making a short, deafening sound. Silence fell. Then something clicked, as if a lock had been turned inside, and the door swung open by itself about a hand's width, letting out a cool breeze that smelled of apples, dust and smoke from the fireplace. - Hello? - Maja called out. Her voice echoed off the walls. - 'Sorry, we've come for... for candy or trick-or-treating! No answer came from inside, only the reverse tick-tick-tick-tick of the clock. The three friends exchanged glances, then Olek pushed open the door. The lock offered no resistance. The hall was high, with a black and white chequered floor. Paintings in heavy frames hung on the walls. The figures in the portraits were looking somewhere just beyond the children, not directly, as if pretending not to see them. Chestnuts and acorns were scattered on the floor, and garlands of dried oranges tied with string hung from the ceiling. From where the dark wood clock stood, the time could be read: 7:03 a.m. The minute hand was moving backwards by successive dashes: 02... 01... 00... 59. - He really is going backwards," Lena whispered. - And now what? - Maybe we should wait until seven o'clock, just... backwards - said Maja, glancing at the map. - There's another sign here. Look. On the bottom corner of the map, just below the drawing of a leaf, a tiny bell was flashing. When Maja lifted the book closer to the flame of the pumpkin lantern standing on the dresser, the bell flared more strongly. On the wall, right next to the mirror, shadows swirled and formed into letters: "Don't look back". The words disappeared as quickly as they had appeared. - 'That's probably not the best advice for someone in a place like this,' Olek muttered, but he tried to smile. The smile didn't work out very well for him. Something meowed. A long, dragging sound came from under the stairs that turned right to the first floor. A black cat slid out of the dark clearance. He had a shiny coat, a white spot on his chest and eyes of two different colours: one golden, the other green. Around his neck he wore a ribbon with a tiny bell, identical to the one on the map. - Hey, kitty... - Lena crouched down, extending her hand. The cat came without hesitation and nudged her fingers with its nose. The bell buzzed quietly, and somewhere in the depths of the house it was answered by an echo, as if a second bell had moved at the same moment. - 'He wants us to follow him,' said Maja, as the cat was already turning and clattering towards the stairs, stopping every few steps and looking over her shoulder. - Let him try to chase us away - joked Olek, although curiosity trembled in his voice. - 'It's just... that "don't look back" thing... What's that supposed to mean? The clock buzzed in its wooden box, as if water was boiling inside it. The shadow of a pendulum drifted down from the walls, and for a moment it seemed to reflect in the mirror not a pendulum but a thread that had retreated into a knot. The cat climbed the first step, the bell sounded once, a second, a third. At the same moment, a thin line of light flashed in the doorway under the stairs - so low that an adult would not have passed through without bending his head - as if someone had lit a match in the crack. - Is there a door there? - Lena squatted down next to Majka, and Olek had already bent down to look into the crack. - There was one, but it was closed - Maja pointed to the leaf-shaped handle. - Only now it's as if... they've woken up. A quiet rustling sound came from above, as if someone had moved a heavy carpet. Then a clatter, as from putting a glass vessel on a wooden countertop. The cat wagged its tail and the bell sounded sharper. At the same moment, the minute hand stopped at 7:00, and the house rang with inverted thumps - not bells, rather their shadow: a short, metallic sound that penetrated the ears like a whisper. One, two, three... - Are we counting? - whispered Lena. - Up to seven - answered Maja. - Because that's what it said. Four. Five. Six. As Seven rang out, the door beneath the staircase vibrated and opened just enough to allow a hand to slide in. A chill and the smell of damp stones gushed from within, and a chestnut rolled to its feet. Then another. And another, until they formed a small pile as if after a game of autumn-winning tag. The cat stretched, looked inside and... did something that made all three of them' hearts squeeze. He nodded, as if he understood their every word. - What do we do? - Olek asked, already crouching by the door. - If we go in and they slam behind us.... - After all, we can always... - started Lena, but she stopped, because suddenly the flame of the pumpkin lantern on the dresser danced and cast flickering lights on the ceiling. For a fraction of a second they arranged themselves into the outlines of a key and a leaf, just like on a map, and then they died down to a silent green glow. - 'I don't think we're the only ones here,' said Maja. Only now did she notice that there was a teapot of milk beneath the painting with the woman in the hat. A single drop trembled on the surface, as if someone had just dropped it. - Did you hear that? - Olek looked up at the ceiling. Something was treading slowly on the floorboards. One. Two. Three steps. Then silence. And then... quiet laughter. Glassy, like bells. Or like someone breathing through glass. The cat jumped into Olek's lap and pawed at his sleeve, as if to say: "There, there". The bell chimed - the same sound answered from the depths of the open space under the stairs. Like an echo from another room. - Good - Olek grabbed the leaf-shaped door handle. - Once... - Two... - Lena added, pressing her cape to her chest. - Three - closed Maja, gripping the book tighter. She held the map so that the greenish light fell on the gap. The door gave way under their hands, revealing a narrow corridor and stone steps leading downwards. The air was cool and moving as they breathed in. In the depths something shimmered. It was as if someone had swung a torch - once to the left, once to the right - and tucked it back. A whisper came from the darkness, quiet as the rustling of a pen on paper. One could have sworn he pronounced one of their names. - 'M... Maya,' someone whispered. Or something. For a split second, all three children froze. The cat jumped down and skipped down the stairs, their bell ringing an ever faster, restless rhythm. Somewhere in the depths, just around the bend in the corridor, a flame suddenly lit up - not green like in a pumpkin, but warmly golden - and someone's shadow moved, growing and growing on the wall, as if approaching towards them.