In the evening, as the mist descended from the river, Lena could hear a low murmur. It reached the house in the Seafront like a rolling pebble on the tin. No one else noticed it, but Lena recorded the hours carefully. Yesterday, the postman brought a piece of paper with a key drawn like a plan of a mystery. On the back were numbers that showed the Old Ferry Crossing quite accurately. In the school library, Lena squeezed the card and showed it to Janek. Janek, who was cracking passwords for the school computers, squinted carefully. Let's check the maps of the town from before the bridge was built, before more traces disappear. One volume was missing from the shelf and the index card was torn. The librarian nodded significantly, as if she knew they were looking for something forbidden. In an old yearbook they found a reference to the Brotherhood of the Second Bank, without dates. After dark, they walked down to the quay, where the concrete remembered footsteps long silent. The river pushed against the bridge, and the Old Crossing creaked as if it were breathing. In the railing they found a metal plate with an engraving identical to the one on the card. Underneath the plate was a bolt, which gave way after three tentative moves. The smell of rust hit their faces as they swung open the narrow hatch over the water. The staircase descended even lower, leading to a tunnel marked with paint falling off. Lena turned on the torch on her phone and the light was swallowed by the wet bricks. On the wall, someone had drawn waves and the sign of a rose, repeating the card. Out of the darkness came the beeping, not of a clock, rather of an engine hidden deep. Then the radio in Janek's pocket beeped, although it was out of range. They heard thirteen short beeps, and then a quiet whisper spoke names. - 'Lena, Janek,' said something from under the water, 'you are a year late. Janek blinked, as if trying to shake the drops of astonishment from his eyes suddenly. - 'It was Morse code,' he whispered, 'the numbers sound like run-off dates. Lena picked up a soaked notebook from the floor, full of smudged crossing stamps. The first page showed the same key, but with a missing pinion. Water began to ooze down the steps, as if the tunnel was breathing faster and faster. Behind their backs a mechanism clicked and the hatch above them closed slowly. The torchlight trembled and stopped on something that was just sliding out of the water.