The tenement at 12 Rain Street had its own smell - a mixture of old wood, freshly brewed coffee and dust passing under the doors of the flats. Although half a century had passed, the wooden staircase still creaked every time Komnata came home. She was eighteen and, she claimed, better at observing the world than participating in it. Every morning, before she dared to descend hurriedly to the university, she listened for a while to the sounds from behind the wall. This was her own ritual - coffee with ginger, a notebook full of unfinished poems and guessing at the riddles of everyday life. Lately, she had noticed something strange: as soon as the first rays of sunlight appeared in the sky, a shadow that did not belong to any familiar object danced on the windowsill below her window. The shadow resembled the shape of a long buckle or an open book. It appeared every day a moment before seven o'clock in the morning and dissolved as soon as Chambers tried to touch it with her finger. One Tuesday, she decided to check where the shadow was coming from. She got down on her knees, looked under the windowsill and found something that, at first glance, looked like a crack in the wall, but when she looked more closely, she saw delicate golden threads in it. From then on, Chambers could not stop thinking about the magical phenomenon. During the day, she felt that something was watching her from around the windowsill - sometimes a breath of air, other times a soft rustling, as if someone was running their fingers over the pages of an old book. One night, when all the household members were already asleep, Chambers sat down by the windowsill and put her hand right next to the mysterious crack. Suddenly she felt a chill and a shiver running down her spine. The golden threads began to glow, and the shadow, which she thought was just a reflection of the ordinary, moved and extended a shadowy hand to her. Trembling with emotion - and somewhat with fear - Chambers leaned closer, extending her fingers towards the mysterious being. At that moment, a light flashed and the room was filled with the sound of what seemed like a distant whisper. Would Chambers dare to touch the unknown? Who - or what - is the shadow under the twelfth sill? The answer waits just beyond the edge of the light....