The clock tower at the end of the station buzzed with night rain as Lena began her duty. She loved the sight: the two giant numerals, the steel ribs, and the unexpectedly warm smell of grease. The world below was a line of lights, and here time ticked louder than thought. For as long as she could remember, she had studied these sounds like a chorus, finding refuge in them. That evening she found a senderless package on her desk, wrapped in newspaper with a faded map. Inside lay a brass key in the shape of a fern and a note: Return it before the second rain comes. Lena looked at the wall between the numerals and saw the outline of the lock, hidden under a layer of paint. The map on the newspaper showed streets she didn't know and a bridge leading directly over the tracks. The key went in smoothly, as if it had been patiently waiting for years for just this move. A door slid out of the metal seam, as thin as the back of a knife and as cool as the morning. She looked inside and the air smelled of pepper, damp paper and something else unnamed. When she turned the key, the whole mechanism vibrated, but the clocks on the facade did not even vibrate. - 'Don't open it if you can't remember where to go back,' muttered Mr Boris, the guard on the ground floor. He stood in the threshold, rubbing his glasses against his sleeve, and watched as if counting the seconds on his lips. - 'These rooms shift your memory, girl; they only give back what you ask very accurately.' Lena bit her lip, but curiosity was like a lift that had already started down. - 'And if you get lost, go back by hearing, not by eyes,' he added, retreating like a shadow. She entered and immediately found herself in a corridor full of pendulums, moving evenly like the breaths of animals. The walls were made of calendars that dropped pages like leaves, though no wind blew. Timetables glistened underfoot, each line vibrating as she spoke her name aloud. A notebook signed in her handwriting, dated in three years' time, lay on a bench made up of sliders. The ceiling throbbed with numbers that lined up the minutes of her childhood and quite alien mornings. As she stopped, one number drifted down like a drop of mercury and disappeared under the sole. She opened the cover and saw a sketch of a tower she had never seen, with a window in the shape of a drop. Someone had added an arrow and the words: The second rain begins when the clocks stop pretending not to hear. Then the pendulums stopped simultaneously, and somewhere further away footsteps sounded, very even and steady. - 'Lena,' said a voice, sounding like an echo from two directions at once, 'do you know what you want back? The door at the end of the corridor swung noiselessly open, and something impossibly familiar flashed through the gap.