The rain was tapping on the windows of City Library No. 12 so thickly that the neon sign opposite dissolved in smears of pink. It smelled of wet coats, dust and the tea that Mrs Veronika always kept in a mug with a cracked ear. Lena and Olek, the last participants in the Reading Circle, sat at a table by the window. Usually it was quiet in the library at this hour, but today a thunderstorm was hanging over the city and the fluorescent lights were flickering as if someone was playing hide and seek with the light. - 'We close in half an hour,' Mrs Veronica reminded us, adjusting her glasses on a chain. - If you want to finish this rebus, it's now or not until Monday. - Now - said Lena without hesitation. She was eleven years old and had pockets full of strange objects: a piece of shiny mica, an accordion-bent map of the city, a paperclip bent into the shape of a star. - This is no ordinary rebus. Look at the signs. She slid a piece of paper towards her brother with a drawing of four arrows and something that looked like a strange alphabet. Olek, twelve years old and a pocket torch always in his backpack, poked his head in. - It looks like a wind rose, only... the letters are reflected as if in a mirror. Ms Veronica smiled and pointed to the top shelf in the reading room, where the librarian's bible read: "Do not touch without asking. - 'Since you're on the hunt for strange letters, I've got something that fits you. Someone brought it in yesterday. It doesn't have an index card. She slid a leather-bound volume off the shelf, heavy, with corners wrought with metal like an old trunk. Stamped on the spine was a golden word: Atlas of Passages and Returns. Lena felt a shiver run over her skin. The title was not in any school inventory. Olek put his hand on the cover and recoiled. - 'Cold,' he muttered. - Like a door handle in winter when you forget your gloves. - 'It's a book, not a doorknob,' Lena snarled, but she also felt that chill, as penetrating as the wind blowing from under the door. She opened the cover. The first page was blank. The second, too. Only on the third did thin, almost invisible lines begin to form what could have been a map. Instead of continents - patches of light, like spilled sugar. - Why is there nothing here? - Olek leaned over, his breath misting over the paper. And then words appeared on the rough page, as if someone had written with a pencil underneath. "For those who can read silence." Lena held her breath. - Read the silence. Mrs Veronica... - 'I have to go down to the storeroom to get some candles,' interrupted the librarian, pointing to the light, which was flickering again. - 'If the lamps go out, we'll be sitting in the dark. Don't move the locking bookcases, okay? - All right," they said simultaneously. And for a minute they kept their word. When Mrs Veronica's footsteps fell silent on the stairs to the basement, Lena leaned over the Atlas again and blew gently on the map. The letters sprouted on the paper like plants after rain: "Between wind and water, bookcase B-3. Pull anchor." - Did you see? - she hissed. - This is no ordinary book. - 'We won't pull anything that's not in the evacuation instructions,' Olek replied, but he was already looking around. The clue was too specific to ignore. Bookcase B-3 stood in the 'Travel and Geography' section. At the end of it someone, long ago, had affixed a brass ornament in the shape of a tiny anchor. Normally, no one paid any attention to it. Today it shone as if someone had polished it. - Just lightly,' Lena whispered, gripping the cold metal. She tugged. At first nothing happened, but then the bookcase trembled and slid out about a hand's width, as if it were peeling away from the wall. From the silent crevice, a chill blew in, smelling of salt and something sweet, like the plum jam her grandmother used to cook in August. - Hello? - Olek slid the torch into the crack. The beam of light disappeared as if it had fallen into a well. - It's not a wall. Lena felt her heart beat a little faster. Another row of tiny letters appeared on the back of the Atlas she held under her arm: "The name of the wind opens that which has no hinges." - The name of the wind... - she repeated. - Do you know any? Halny? A breeze? Zephyr? - Halny is from the mountains, the breeze from the sea, and the zephyr was in the poem," Olek muttered. - But they are just words after all. - 'Words are the keys,' said Lena, remembering Mrs Veronica's favourite phrase. She leaned into the gap and whispered: - Zephyr. Something clicked. The bookcase slid open wider, revealing a narrow metal door that couldn't have been there before. They had no hinges. Instead, in place of a handle was a drawing of wind: swirls, dashes, tiny dots like raised sand. Through the illusory window you could see the sky - but not the one above the city. It was dark and had two moons, one as thin as a fingernail, the other bitten out, as if someone had bitten into a cookie. Olek swallowed his saliva. - This is a bad idea. - We don't know yet whether it is a bad or a good idea,' Lena replied. - But this is the only idea we have. The door gave way silently, as if it weighed nothing, and opened onto a corridor that could not be fitted into the wall of any building. In front of them stretched a platform of hexagonal slabs as white as eggshells, suspended above water that looked more like sky. Everything around sparkled with a fine dusting of light, as if someone had scattered glitter across the dark sheet. From afar came a noise: not of the sea, not of the street, rather the sound of pages being turned. - 'Miss Veronica...' began Olek, turning away, but when he looked back, the bookcase was still in place, though now it was just a dark rectangle. On the other side, where the reading room should have been, something that resembled a reflection was flickering. You could see inside the library, but outside the windows it was snowing. Snow, in September. - 'Don't turn around,' Lena said, although she herself felt like grabbing her brother's hand. - 'We're walking a bit. If it's bad, we'll go back. - And if the door closes? - Olek asked. - Then we'll open them. We know the name of the wind. They took the first step. The hexagonal slab beneath Lena's foot flashed with a soft light, and right next to it, a tiny dot appeared on the sheet of Atasu she was holding. The dot moved forward, exactly to the rhythm of their steps. On either side of the platform, at some distance away, stood poles with placards that rotated without wind, clicking silently. Lena stopped at the first one. There were names there, written in script that sprouted from the map like shoots: "Nests of Clouds", "Remembering Stones", "Town of Two Shadows", "The Garden that Sleeps Not". The arrows trembled, as if they could not decide which way to point. - This is... - Olek broke off and just shook his head. - If this is a joke, it's the best one anyone has ever made for us. They walked on, taking their steps carefully, although the slabs seemed solid. Beneath them, the dark water - or sky - moved unhurriedly, and in its depths something could be seen flickering with signs like skylights arranging letters. It was impossible to read them because they changed before the eye could grasp them. - Can you hear it? - Lena put her hand to her ear. The noise of turning pages grew, joined by other sounds: a whisper, as if someone was learning a poem by heart; the rasp of a braking tram; the splash of water from the tap; the stamping of feet in the school corridor. All at once, but strangely harmonious. At the end of the platform stretched a circular square. Its centre was a shallow basin with water so smooth that it reflected not them but something else: the interior of the library, but with different bookcases, a different lamp, a different Mrs Veronica, who had her green hair pinned up in a high bun. Someone - perhaps they? - was walking there with a book under his arm, but moving as if in slow motion. - 'It's a mirror, but not like a normal one,' whispered Olek. - It's... - It's a signpost - finished Lena. - Or a window. She leaned over and brushed the water with her fingers. The ripples spread concentrically, without a drop, as if she had touched glass. At the same moment, from the other side of the square, the light came on. Warm, amber, like from an oil lamp. Once, twice, a third time, as if someone had walked by with a lantern and shook it so that the light rippled. An invisible bell hung over the square. It sounded softly, then a little louder, like a clock that had just remembered it had something to announce. On the edge of the basin, next to their feet, words scrawled in thin script glowed softly: "Passengers, prepare a response." - What answer? - asked Olek, rhetorically, as there was no one around to answer him. - Maybe it's a slogan," said Lena. - Or a question for which there is not just one solution. Footsteps, if they were footsteps, were approaching. Behind the light of the lanterns, a shape began to become clearer. First the shadow of a wide-brimmed hat. Then the fragment of a coat that seemed woven from maps, with a thousand tiny lines and dashes. The colour of the sky seeped through its edges. The lighthouse really wasn't a lighthouse. It looked like a moon suspended in a metal hoop, sprinkled with dust. - Do we... - Olek began, but his voice trailed off. On the other side of the platform, the one they had passed, something trembled. The arrows on the plates stopped spinning and all at once pointed in one direction: straight ahead. The nautical smell of salt became more intense, and on the pages of the Atlas the dot that had been theirs fluttered like a bird in the palms of their hands and suddenly stood still. Next to it appeared a sign they did not know: spiral, like a snail, and three dots at the bottom. The light of the moonlight went out for a second and flared up again, this time just at the edge of the square. The hat's shadow stopped a step away from the basin, so close that Lena could see something reflected in the water: not a face, not a hand, but a sketch of a hand - the outline of fingers drawn in lines. - 'Passengers,' spoke a voice that sounded like the hum of pages being turned, though it pronounced the words clearly, 'give the word of passage. Lena looked at Olek. Olek looked at Lena. The atlas trembled in her hands ever so slightly, as if it could be a breath of wind. A thousand words popped into Lena's head at once: key, home, return, star, zephyr, request. She had to choose one. She breathed quickly, trying to hear her own voice among so many sounds. - A word of passage... - she repeated, and the shadow of the hat leaned back a little, as if waiting. - Maybe it's...