Lena turned seventeen in the flat above her old grandfather's clockmaker's workshop. Since her grandfather's death, all the clocks near her had started to go evenly, as if they were ashamed of being late. That morning the trams rapped as usual, but there was a ticking in the kitchen of something she hadn't put on the table. The sound was soft, almost instantaneous, breaking off exactly when she blinked. On the windowsill lay a parcel in paper strangely soaked in the smell of pungent ozone. The address was written in ink that refused to dry even when touched with a finger. Inside she found a key with an engraving of the moon, a handful of black sand and a card: "Library of Wind and Ash - entrance at the shortest shadow". She understood at once that it was about the south and the water tower that had been haunting by the tracks for years. Her grandfather had once told her that it was where you went down under the city if you knew how to count the breath of the stones. By twelve o'clock its shadow had shrunk to a narrow line on the floor. The tower was empty except for the rust and wind rose mosaic in the middle of the room. Lena poured sand into the point where the compass needle pointed north, and pressed the key into the invisible lock between the tiles. The air trembled, metal clanked deafeningly, and a flap leading down opened. Beneath the tower hung a model of the sky, slowly rotating like the breath of a sleeping animal. Lights ran along the walls, which pretended to be currents, linking the stars into unknown constellations. On a desktop, covered in a thick layer of dust, lay an atlas with a cracked leather back. The title sounded ordinary but evoked a shudder: 'Atlas of the dark rivers' within it. When she touched the cover, ink flowed from the letters and spilled into troughs that trembled as if they remembered her name. The map showed the city, but its streets flowed like rivers, twisting time by minutes. In the margin was her grandfather's note: "The guardian will not return, the streams are silent without a tuner". Lena swallowed her saliva and counted her own heartbeats, as he had taught her as a child. A third breath, a fifth pause, and the thinnest stream began to glow a faint blue. Then, down below, it roared, and a long shadow slid up the metal steps, as if someone was carrying a coiled ladder. She slammed the atlas shut, but the glow did not go out, it just moved to the key. The brass heated up like a stone on the beach, and the planetary model wailed quietly in the cold wind. - 'Hand over the instrument, Clockwork,' said a voice from below, effortlessly covering the entire stepped window. Lena squeezed the key tighter; the hands of all the instruments suddenly stopped and the model began to rotate faster. The sound of a tram cut the silence, though they were deep underground; then a silver-gloved hand slipped out of the shadows, reaching for an atlas.