Lena always told herself that her life was going on somewhere next door. The city - grey, bustling, predictable - seemed to her to be a wrapper, rigidly packaged, difficult to break through. A tall block of flats with cursive number letters on the facade hid dozens of flats, identical staircases and endless stories of neighbours whose faces she knew only by sight. But on this night, the light on the third floor was not on as it always was. She was returning from her lesson late, through deserted squares, passing a lone dog and lantern lights reflecting in puddles. She knew by heart the layout of the stairs, the distinctive creak of the handrail at the fourth step, the coffee stain on the pale wall. But when she reached the second floor, she stopped. On the wall, someone or something was casting a strange, pulsating shadow. Lena swallowed her saliva and cautiously walked closer. It was just a metal key hanging from a hook, but the shadow seemed too long, too sharp. She looked at the key - old, covered in rust, as if no one had used it for years. Next to the hook someone had stuck a note: "Sometimes all you need is to open the door". Lena gripped the key with her fingers. At the same moment, she heard a rustling in the bottom of the cage and a quiet clatter - as if someone had stepped inside, even though the front door should have been locked. She tightened her hand on the key, her heart pounding like a hammer. She wondered who else knew of the key's existence, and what - or who - was waiting behind the door that could be opened with it. There was something different in the air than usual, an intangible energy that caused goosebumps. Lena looked at the closed door at the end of the corridor - the one that always stood impassively closed, as if it led nowhere. Did she have the courage? She approached slowly, the key trembling in her hand along with her. She heard another step behind her - and then....