There's Something Wrong with the Empty Building, I Rely on the Sounds to Figure It Out

In an unfinished building on the edge of the city, a barefoot woman died ten years ago. From that day on, every night late at night, the sound of footsteps at a steady pace would be heard in the building. One floor, two floors, seven floors, sigh, and then step back. Day after day, year after year. Others can't hear it, but I can. Not only could I hear her footsteps, but I could also hear the whispers in the wall, the scratching in the soil, and the breathing behind the crack in the door. I know what she's looking for. I also know that this is just the beginning. When you can hear the voice of ghosts, you will find—— This world is much dirtier than you think.