In Leeward, summer smelled of tar, needles and salt spray. The sea changed colour every now and then: once it was like steel pot, once like green glass. At the end of the cliff stood a lighthouse - white, with a red lamp hat - that had been closed for years. At least, that's what Grandma Hela said when Tola asked why the old flashes were no longer visible in the evenings. Until that night. - Have you seen it? - Tola perched on the railing of their little base in the old fishing shed. - Three short, two long, three short again. And so on several times. Iwo raised his binoculars and peered into the lighthouse, which darkened against the setting sun. He was twelve years old, with a penchant for jotting down everything in a checkered notebook and a headlamp torch that he loved like his own invention. - 'It's not just a marine signal,' he muttered, scribbling something in his notebook. - The lighthouse is disconnected from the grid, remember? The lady at the tourist information was talking about it. Someone must have... you know, got it working somehow. Kajtek, the lowest of the three but the fastest on every fence and every dune, grabbed the wooden bait box that held everything they could possibly need: a compass, spare batteries, a bandage, two apples and a whistle. - So what? Shall we go? - he smiled as if he had just announced the best part of the day. They went at dusk, when the seagulls screamed over the harbour like belated alarm clocks and the first lights of the boats appeared on the water. The path to the cliff winded among buckthorn and dry grasses. It was quiet, except for the sea crashing against the rocks time and again with its breath. - 'Watch out for landslides,' said Tola, who had the best understanding of the terrain. - Yesterday the rain had watered the slope. The gate to the lighthouse was locked with a thick chain, as rusty as an old anchor. But Kajtek knew the narrow clearance between the bushes and the stone wall, the path of foxes and curious children. They walked quietly, as if each step could wake the whole cliff. The door to the tower had a heavy iron handle. Tola pressed it carefully. To their amazement it creaked briefly, freshly greased. - 'Someone's been here recently,' said Iwo, putting his hand to the cool wood. - 'Not long ago. Very recently. Inside, it smelled of metal and old oil. A spiral staircase climbed upwards like a black spring. On the wall hung a plaque with a faded lamp service plan, and next to it yellowed photographs: former lighthouse keepers with the wind in their hair and smiles as simple as if they had never been in trouble. - See - Tola pointed to the dust on the steps. - The footprints of shoes. One footprint is bigger, the other smaller. And they are fresh. - 'Maybe it's a rat,' whispered Kajtek, but he immediately laughed, because a rat's footprint would hardly look like it was from a rubber glock. They climbed slowly. Every few steps they stopped to listen. At first they could only hear their own breathing and the deafening hum of the waves, which sounded like a distant train in the tower. On the first platform they found discarded work gloves and an old brass telescope engraved: 'Crew No. 7'. Iwo wiped the glass with the corner of his T-shirt and tucked the telescope into his backpack with the look of a man who had just received a treasure. - 'We're in a hurry,' urged Tola. - Before night falls. On the second platform hung a board with the types of lantern flashes: short, long, breaks, all labelled with equal numbers. Iwo compared the rhythm they had memorised with the markings. - 'Nothing fits here,' he said finally. - It was as if someone had invented a new code. By the time they reached the mountain itself, the light of the last day had already faded almost to grey. The lamp room was circular, with glass all around and a huge lens whose striations formed hypnotic circles. A llama trunk stood like a voiceless sentinel. And yet something was happening. A thermos stood on a stool. Kajtek unscrewed the cap, wary as a cat at an unfamiliar box. Warmth and the smell of tea with raspberries hit from inside. - 'Someone is very close,' he whispered. At the same moment, the lens of the lantern vibrated. It was not switched on, yet a faint glimmer slipped through the glass, like the reflection of the moon. The luminous stripe traveled along the wall and stopped on a piece of sheet metal that had hitherto looked like an ordinary part of the structure. Something inside clicked, metal against metal, as if someone had turned a hidden mechanism. - Hear that? - Iwo took a step back. - It's not the wind. The sheet deflected millimetres. A chill gushed through the gap, smelling of stone and salt. Then the panel slid in completely, revealing a narrow corridor deep into the cliff. It descended steeply, and at its end a pale greenish light flashed, the kind that buoys have at night. On the threshold lay an envelope. Thick, made of cream-coloured paper. On the top, in pen, were written three names: "Tola, Iwo, Kajtek". The letters were neat, a little old-fashioned. - Don't you get the feeling that someone invited us here? - asked Kajtek, although it sounded like a sentence from a book, not from their ordinary summer at the seaside. Something neither of them had anticipated. Tola felt her heart beating faster, somewhere all the way below her throat. Iwo's eyes widened, already calculating in his head all the possibilities. Kajtek adjusted his rucksack strap and reflexively squeezed the whistle in his pocket. - 'We'll do this sensibly,' Tola decided. - First the envelope. Then we'll see what happens next. The few steps to the threshold seemed longer than the entire climb up the stairs. The lens behind them murmured quietly, as if something in the mechanism was waking up from a nap. A sound they couldn't name came from below - a bit like a hiss, a bit like the very distant echo of a wave bouncing down a stone tunnel. Tola held out her hand. At the same moment, somewhere in the depths of the corridor, something moved and the shadows trembled, as if someone had reached out there too, only from the other side....