The lighthouse at Oak Cliffs looked like a giant, glassy flower stuck to the rock. It hadn't been lit for two years - modern buoys and satellites had taken over - but it still stood, silent and proud, with its lace of metal railings and salt marks on the glass windows. Tourists took photos by her, seagulls circled and the waves muttered something to the stones. Zosia liked to count. Waves, raindrops, steps of stairs. She carried a small checkered notebook and a pencil in her pocket, which she wiped off with a knife so that it was always sharp. In the same pocket she kept the found: a bubble amber, a star-shaped button, two glass beads. Franek, on the other hand, carried a string, a penknife and a sheet of Morse code. He was a Boy Scout, could tie a knot that looked impossible to untie, and always had a plan. At least, that's what he said. That day, the air was as clear as after a storm, though the sky was blue. At eleven fifty-five Zosia and Franek were sitting at the end of the breakwater, dangling their legs over the water. They looked at the lighthouse, because there was always something to look at there, even if nothing was happening. - Do you remember what Mrs Aurelia said? - Zosia asked. - That the lighthouse could speak to the ships when the fog was as thick as porridge. Mrs Aurelia lived in a house above the harbour. She had silver hair pinned up in a high bun and a radio that collected voices from all over the world. She used to be a radio operator. She used to laugh that the sea had its own alphabet, you just had to know how to listen to it. The clock on the town hall tower killed noon, and at the same moment the lighthouse flashed. Once. Zosia closed her eyes. Again. Briefly, briefly, briefly. A pause. Long, long, long. Pause. Short, short, short. - It's SOS - muttered Franek, already with his pencil over the page. - 'But then... look! The light sent up another sequence of flashes. Zosia counted in a half-hearted voice, and Franek counted on dots and dashes. Their hands trembled a little with emotion; the lantern had no right to blink. It wasn't plugged in, they said. And yet it was blinking. - Z... N... A... - whispered Franek, running his finger over the chart. - I... D... WRONG. "FIND." The air suddenly became heavier, as if the sea had held its breath. - What next? - Zosia leaned over so that her pinned-up hair touched the paper. - G... £... O... S - Franek raised his eyes. - 'THE VOICE OF THE LIGHTHOUSE. Who's broadcasting it? Seagulls beeped over their heads. More flashes sprinkled from the tower like sparks. - K... L... U... C... Z - read Franek faster and faster. - "THE KEY WHERE THE SEA SOUNDS LIKE A BELL". Zosia and Franek looked at each other simultaneously. - The bell of the sea - they said at the same time. At the end of the pier was a circular concrete well with a narrow gap. When the waves were high, they would hit the underground chamber so that there was a deafening metallic tone in the air. The children called it the Bell of the Sea and checked to see if it was 'playing' today. On this day it played long and low, like the serious bells of old. - 'There are a few minutes left,' said Franek, looking at the hands. - If it means anything at all. They ran along the pier, the winds tickling their ears and the salt doing to their tongues what salt always does - he wanted one more, one more bite of air. There was no one standing by the well. The tourists had gone for ice cream, the fishermen had settled into the shade, and the sea was humming its low song. Zosia began to watch the railings. She had learned that when someone hides something, they leave a mark. A scratch. A scratch. A slight difference in the colour of the paint. Franek checked the underside of the benches, the hooks, the screws. - 'Three fish,' Zosia said suddenly, pointing with her finger. On one of the metal slats, right at the edge, someone had scratched three tiny fish: two facing left, one facing right. - As in the coat of arms of the smokehouse 'Three Silver Fish',' muttered Franek. - Maybe it's a sign. Zosia touched the middle fish. The metal was cold. She pushed gently - the slat bent, clicked. Something slid out from under the railing: a flat tin casket, parched from the salt. Inside rested a small brass key wrapped in waxed paper and a note with writing as even as the horizon line: "12:15". - Three minutes to go,' hissed Franek. - 'Do you know what that means? Zosia was already running. The lighthouse, though it seemed close, stood high, and the stairs cut into the rock could go on forever. Halfway up, they turned around for a moment; the lighthouse was not lit. The sea rumbled in the well like a great drum. At the top, the gate was locked with a thick padlock, but to the left, in the shadows, hid a lower gate with a small lock like that for a letterbox. The key fitted perfectly. It jingled quietly like the groan of an old piece of furniture. The wicket gave way and a chill hit the children's faces. It smelled of oil, dust and salt spray. It was semi-dark inside, but strips of light peered in through the gaps in the blinds, drawing on the floor of the staircase like the keys of a huge instrument. - 'The clock,' said Zosia, pointing to the dial on the wall. - Twelve fourteen. - Bottom or top? - whispered Franek. To the right was a corridor with a sign saying "AGREGATE". Straight up was a winding staircase, so narrow that you had to place your feet very carefully. Somewhere above, something rustled, as if someone was moving a chair. - Upstairs - Zosia decided. Her heart was pounding in her chest like a wild ball. Climbing up was like climbing up the inside of a snail. The walls shimmered with greenish paint; every few steps they passed their windows, which for a moment showed the sea - once near, once far - and the harbour, and the red roof of Mrs Aurelia's house. On the platform just under the glass cap of the lighthouse stood a wooden table, a radio with dials, a metal toolbox. In the corner - a clock with a pendulum that swung slowly, as if it didn't quite remember that the world was passing by. - 'Twelve fifteen,' whispered Franek, looking at the hand that had just touched the numeral. Something in the mountain vibrated. A thin sound slipped through the glass, barely higher than the whisper of a rut. Then - a flash. One, quick as a blink. Zosia trembled. The light spilled across their faces, went out and flared again, shorter this time. Briefly. Short. Long. Pause. Short. Short. Long. Short. Short. - Z... O... - Franek started to count in his mind, but the words spilled out of his mouth. - S... I... A. Zosia seemed to feel her name gain weight and fall from above straight at her. The light went out again, something rasped in the mechanism, as if a hand that wasn't here was trying to activate a long-forgotten mode. - Stop,' she whispered, not knowing to whom. - Who is there? The radio on the table hissed. There was a short crackle in the speaker, then a second, longer crackle, like an ocean in a metal box. The dials vibrated, though no one touched them. The clock struck once, a second, a third, counting down some silent 'now' of its own. Then downstairs, by the door, something creaked. Someone had entered. Footsteps stepped slowly, surely up the stairs. A shadow, criss-crossed by strips of light, grew on the wall like a climbing plant. Zosia squeezed the brass key in her hand so tightly that she felt its gouges. Franek shifted his gaze from the radio to the door. The handle moved barely, as if someone was checking to see if they were really alone. Then she pressed resolutely. The wood groaned and the air around them became as thin as parchment....