There was only one rule: don’t open the door.

That was made very plain by Mia's grandmother, who held Mia's hand while speaking in a tremulous voice. Mia heard a gentle, purposeful knocking as soon as she entered the dusty old house, though, like though someone was waiting outside and aware of her presence.

She made an effort to ignore it, concentrating instead on unpacking her things and lighting the antique candles. However, the knock was louder this time, a low rumbling that sounded as if it were rattling the entire house. A cold shiver ran up her back. She was intrigued—who would it be? How come her grandmother would prevent her from responding?

An hour went by. The knocking became more urgent, more loud, almost begging. Like fingers grasping for the entrance, shadows flitted on the walls. Her heart thumping in her chest, her palm shook as she went for the handle. The music was making her crazy, even though she knew she shouldn't.

When she did open it, all she saw was blackness, a vast, unending emptiness. Subsequently, a chilly murmur floated across the quiet.

"I appreciate you letting me in."

The knocking resumed as the door swung shut. However, it originated from within the room this time.