At the Bliznica, the sea had a habit of biting the shore bit by bit, and the wind gave the daily conversations a snarling accompaniment. The lighthouse on the headland had been silent for years - ever since the storm that cut the sky into strips and burned through the cables like threads. Even so, every now and then someone would swear that they saw a narrow beam glide across the water for a second at 04:13, as if someone unseen was rearranging a huge mirror. Nela heard these stories at the bus stop, in the fishmonger and in the library, but she liked listening to the waves best. Collecting sounds was her obsession: rusty hinges, the clatter of water against boat hulls, the rumble of an old lift in a tenement. She had a small recorder with a battered casing and a capacious memory card, and there was always an extra microphone tangled in her backpack, wrapped in a sock so it wouldn't catch the wind. Igor, her best friend from the cage next door, carried boxes of parts, wires and bent manuals in the same gate. He was building radios from found things and a weather station on the balcony that would blow rain before the first drop even fell. One September afternoon, as the sun was heating up with its last strength, Nela recorded something strange. The waves at the breakwater didn't sound as usual. In clicks and hums, if you sped up the recording, there was a short series: three shorter ones, one longer one, pause, again. She took it to Igor. "It looks like a signal," he said, pushing his glasses, which rarely landed on his nose anyway, to his eyes. - "Maybe someone was playing with a buoy. Or... you know... someone trying something." Nela rewound the recording and pressed pause on the value 04:13. It was all a coincidence, but the row of numbers reminded her of stories. "See, it's right here. This is the time the sequence starts." Igor stifled a laugh, though there was a glint in his eyes. He pulled the cable to his latest invention: a wave-everything receiver composed of several modules. He switched it on, turned the knobs. There was a beeping in the loudspeaker, then a humming, until finally everything calmed down and a monotone voice flowed into the silence, as if someone were reading from a sheet of paper: 'Owl thirteen, sequence C, time: zero four thirteen. I will repeat. Owl thirteen, sequence C..." They behaved like children who were suddenly promised by someone that they would find an entrance to another world in the house under the table. Besides, they had both long since outgrown their belief in coincidences. When something started to form rhythms, Nela could hear it in her bones, and Igor couldn't turn off his curiosity. "Owl thirteen... that could be the name of the station or... a code name," he muttered. - "And the C sequence? Maybe it's the order of the books." "Books?" "You know, like in a library. Signatures." So they went to the library. Ms Teresa, the librarian in a faded mint-coloured jumper, always said that the two of them had a unique tendency to invent trouble between the bookcases. This time the trouble wasn't hiding deep. On the railing of the staircase, someone had recently scratched out the numbers with a fingernail: 82-91/1913, and the dots between the dashes were as even as if measured by a ruler. "Please don't carve in the library," called out Mrs Teresa from across the room, but Nela already understood. 82-91 were the signature of literature in foreign languages, and 1913 was the year of publication. After a brief trail in the section where it smelled of dust and salt from the clothes of the fishermen who came here to read the newspapers, they found a thin volume: "Lighthouse Keeper's Service Diary. 1913." Someone had added a tiny line with a pencil next to one chapter. On this page lay a pressed leaf of a sea plant, fragile as glass. The text marked with an arrow spoke of the jammed door to the lens chamber and the fact that the rotary mechanism had to be oiled every day before dawn. In the margin, in a different handwriting, small and nervous, was a note: "Descent under base, key in salt. Light remembers." Nela raised her eyes. "Key in the salt?" Igor put his finger to his lips, then pointed to the window. They walked out, almost running, onto the wooden platform, which trembled underfoot as if alive. At the end where the wood was most gray, in a crevice between the boards covered with salt, they found a metal object. It looked like something between a nail and a bone needle. When they cleaned it out, it revealed an old key, with a tooth as uneven as a shoreline. Evening came quickly, as if the sun had grown weary of this whole game of trick-or-treating. The lantern on the hill drew a black, slender outline in the sky, and the lip of the clouds stopped above it, as if it were about to settle. Nela and Igor climbed a path strewn with shells that crunched under their shoes. They took torches, a recorder, Igor's receiver and their usual courage, which often turned into foolish bravado, but today they needed it in its full version. The door to the lighthouse was heavy with peeling paint. Someone had once tried to open it with a crowbar - you could see the marks - but without success. Nela slid the key into the lock. It turned with resistance, as if someone had slept very deeply inside and did not want to get up. The latch let go with a sound that echoed through the stone interior. Inside, it smelled of tar and rust. The wooden steps of the winding staircase against the wall were tattered, every other one had a chip from too heavy shoes. Someone had once painted crosses on the walls, but the paint had cracked and the marks had surfaced again. Nela switched on the torch. The light glided over the railings, over the sign with the worn-out "Do not enter - emergency" sign, over the cobwebs that rippled as if they were breathing. "Keep it down," whispered Igor, though they both said nothing. - "Do you hear?" She heard. Up above them, something was ticking. Not like a watch, more like an old machine that had been abandoned and only one spring had some life left in it. Igor placed the receiver on the cold stone, connected the short cable to the metal railing and pressed the switch. Silence flowed from the speaker, broken after a moment by a grunt, and then a voice - the same, unfamiliar and matter-of-fact: "Owl thirteen, sequence C, time: zero four thirteen." "See? It wasn't just by the sea at all." "Where does it broadcast from?" "Or where it's reflecting from." They walked higher. Underfoot it creaked. There were wet, fresh footprints on the seventh flight of stairs - the distinct shapes of the soles, as if someone had walked up here just before them with wet sand stuck to their shoes. Nela flicked her torch at the handrail: there was an oily handprint on the metal, darker in colour than rust. Nela touched it - it was plain damp and salt, nothing more, and yet a shudder ran through her. On the mezzanine they came to a lower door, which Nela did not remember from any of the pictures of the lighthouse eagerly repeated in tourist brochures. The door had a small round window at the top, scratched like old vinyl. Darkness shimmered behind the glass. The key in their hand fitted the lock as if it had been cast into that very hole. It popped without resistance. Behind the door was a narrow gallery that had no right to be here. It led not upwards, but sideways, into a brick tunnel inserted into the wall of the tower. The chill was greater than below, and the air smelled of metal and dill. Someone had scrawled a diagram on the bricks in chalk: a circle, arrows, a sequence of numbers. 04:13 was repeated several times, like a refrain. "It looks like a bypass," whispered Igor. - "Maybe the lighthouse keeper had a shortcut under the lens." "Or a way for someone who shouldn't come in here." At the end of the tunnel hung a spring-loaded bell and a sheet of paper, the paint on the letters half dripped off. They only managed to read: "Auxiliary entrance". Behind it - another door, with thick moulding and a shiny new lock. The newly installed piece among the old rust looked alien, like a promise and a threat at the same time. "We don't have a key for it," Nela said, although she wasn't sure herself whether she was saying it with relief or disappointment. Igor ran his fingers over the skirting board. "Wait." He leaned over and looked into the gap. On the ground, on the other side, was the shadow of something metal. A warning? Or... curiosity materialised in iron. "Do you hear?" - This time it was Nela who froze, gazing upwards. Above, just above their heads, there was a protracted groan, followed by a quiet swish. It was as if a large lens, immobile for years, had suddenly moved a millimetre. A crackle came from the receiver speaker and a new string of words, this time not as even as before, as if someone was speaking directly into the microphone rather than reading: "Owl thirteen to Base. Alignment... rearrange... zero four thirteen... confirm reception." "Who's transmitting this?" - Igor moved away from the door as if something was about to come through it. One of the torches went out, the other blinked. Time in the lantern seemed to thicken. Nela put her hand on the cold doorknob. The lock clicked, the way keys click in your pocket when you're looking for the right one - by itself, without moving your hand. The door vibrated. A very faint, icy glow shimmered in the crack, as if someone on the other side had moved a mirror and a sliver of light deposited itself on their cheeks. And then, quietly, precisely by name, someone whispered from the other side: "Nela."