Nadia was fourteen years old and had pockets full of screws and ideas. After a storm, the sea had pushed away the sand on the beach, revealing the remains of a decayed pier. In a crack in the wood, she found a brass token with a lighthouse and the date 1913. Under the light of the late afternoon, the metal shimmered like the scales of a minnow. - 'It's probably a token from a game of caps,' muttered Maks, her neighbour. Nadia merely raised an eyebrow and slipped the find into an old tin. With the tin, they ran to the marina, where the library was housed in a shed. Mrs Rose, the custodian, knew every story, even the untold ones. In an old log book they read about a door under a dune and three flashes. The token fitted perfectly into an indentation on a dusty box hidden behind a globe. A drawer with a map on canvas and a short, strange rhyme slid out. - 'Just be careful,' warned Rose, 'legends can sometimes be cleverer than bold people. At dusk they set off for the dunes with a compass, headlamps and a folding shovel. The wind carried salt and seaweed, and the lighthouse winked like an impatient guide. The map guided us through twisted pines, a broken buoy and a shadow that flashed three times. Between the hills they found a stone slab with a circular groove for a token. The metal clicked, the sand hissed and a dark hatch opened in the ground. - 'We're going down, but we'll just check the entrance,' Nadia decided, clutching the strap of her backpack. The steps were slippery and the walls were covered with engraved ship names and initials. Somewhere deeper it clattered steadily, like a distant telegraph losing sharp letters. Nadia knew the Morse alphabet from the radio circle and whispered, counting the beats. - It's S O S, and then numbers, probably coordinates, but some inverted. Maks' headlamp flicked on, as if something had blocked the light for a split second. A metal door with a brass wheel and a rusty plaque emerged in front of them. A quiet hum sounded from behind the door and the wheel began to turn on its own. On the plaque, a half-articulated name could be seen, missing two letters. Maks took a step back as a cold blast brought the smell of wet ozone. A scrabbling sound came from the darkness, as if someone was dragging a chain across the wet concrete. Nadia lifted the token, and then the wheel vibrated faster, snapping the tongues of the locks. Someone on the other side also grabbed the mechanism, very determinedly.