It was the first week of the graduating class at the old high school by the river. The yellow brick glistened after the rain, and the clock above the entrance trembled like a cold pigeon. Lena liked school sounds: the creak of the door, the rustle of the chalk, the sure tone of the bell. On this day, however, she heard something different, a quiet announcement that didn't fit into the timetable. On the notice board, amidst the competitions and appeals, hung a fresh print with the round stamp of the headmaster's office. They went down with Oscar to the old wing, where the corridor smelled of chalk and wet linoleum. The card was nailed with a new pin and the ink looked as if it had only just dried. "Mandatory class: Room 13, 00:00, attendance verified." - read Oskar, blinking in disbelief. - A joke? - Lena touched the stamp; it was real, with a microscopic city crest. Above their heads, the fluorescent light blinked, as if someone was blinking in response. They went to the gatehouse. Mr Roch, who knew every key and every noise, nodded gravely. - 'Room thirteen is closed from flooding, kids. After six o'clock don't hang around in the old wing, the lights are going crazy. - His bundle of keys sounded anxiously as he looked away. They returned to the board, but the piece of paper had disappeared and a lighter rectangle was left on the cork. - 'I've got a picture,' whispered Oskar and showed his phone with a clear date and time. A single, dry 'ding' came down from the ceiling, though the ringtone was silent. In the evening, Lena could not let go. At 11.45pm she waited at the gate, and Oskar came in with a torch in his pocket and an unhappy smile. The gatehouse was dark, with only a still steaming cup and a crumpled newspaper left on the desk. The gate stood ajar, as if someone had forgotten the last lock. They entered sideways, along the hedge, and slipped through a side door that gave way with a quiet sigh. Inside, the corridors glowed pale from the emergency lights, and someone had drawn arrows on the floor in chalk leading deep into the wing. The clock in the lobby, the one with the cracked dial, showed 23:59, as did all the others. The arrows ended at a door with a new brass plaque: "Room 13". A low murmur came from inside, as if the class was repeating definitions in a whisper. - Can you hear? - Oskar put his ear to the wood. So did Lena, and she stiffened as someone on the other side mentioned their names, clearly, in the tone of a teacher checking a list. The phones vibrated simultaneously; a new timetable appeared on Lena's screen: "Semester Night, Room 13, Silence Methods". The bell swelled, as if the building was taking a deep breath, and struck with the first, heavy beat. Lena grasped the doorknob; it was icy and the lock clicked, as if someone from inside had just invited her in. A thin streak of light moved under the threshold, and the shadow of someone's hand cut her in half.