The autumn rain drummed against the windows as Lena opened the Under Yew library. She had been given the key by her librarian aunt to help carry in boxes of catalogues. Behind her walked Oskar with a torch and a backpack, feigning bravery with a lame smile. Reading Night had been cancelled by renovations, but curiosity drew them like a strong magnet. Through the glass, they could see the river, dammed up as if it was guarding something beneath the city. The warehouse smelled of lime and old paper, and the corridor led straight up to the stage. Lena searched for her great-grandfather's notebook, who had written notes here during the flood of 1903, and found tide charts, sketches of cellars and a sentence: the underground connects to the river. Behind a bookcase, she moved a plywood panel and discovered a staircase, as if it were just waiting for her. A rodent-proof bell dangled from the ceiling, which moved without wind and fell silent. They descended cautiously, and the echo echoed each step as if someone was walking half a step later. The walls were cold, the ceiling low, and a rusty card catalogue stood at the end. In the first drawer lay a pocket watch that ticked backwards, although the spring was dead. Oskar whistled quietly, and the compass on Lena's phone suddenly spun senselessly. Then they heard a whisper, as if from pipes: Give back the clock, and a long, wet pull. The paint on the pipes cracked into the shape of maps, and droplets dripped like a persistent metronome. "It's the wind, the old installations," Oskar said, but his fingers trembled on the torch. Lena turned the watch over and read the initials A.G., the same as in her great-grandfather's notebook. The upstairs door slammed open on its own, and the stairs answered with a short, muffled groan of wood. On the stool, a dusty map of the cellars had an X next to the word Tie, just below the reading room. The whisper came back, clearer, with pauses like a cough: Give back the clock, Lena, give back the clock immediately. When she rubbed the glass, a dry residue of flour or dust flashed under the glass. At the end of the shelf someone had left a fresh shoe mark, no bigger than hers. "I didn't say my name, did I?" Lena asked, looking straight at Oskar. "Let's go to the Scroll and check before the torch runs out of battery," muttered Oskar. The corridor narrowed, the air grew heavy and a black mirror of water flashed behind the archway. On the riveted door someone had scratched an arrow and the phrase: Don't wake that which sleeps. When Lena touched the doorknob, it was warm as a hand, and on the other side something knocked. A rivulet of water slid from the ceiling and fell straight onto the watch, hissing like a needle. A pebble rolled somewhere in the passage, as if someone had just stepped back a foot. The watch ticked back a second, the light flicked on and the handle began to turn slowly.