The folder contained only two items: a low-resolution image of a hallway that looked remarkably like his own apartment building, and a text file named READ_ME_BEFORE_THEY_DO.txt .

He walked to his front door and looked through the peephole. The hallway was empty. But when he returned to his computer, the image in the folder had changed. The shadow was closer. The file size of began to grow, byte by byte, as if it were recording something in real-time.

Elias grabbed his mouse to delete the folder, but the cursor moved on its own, dragging the recycle bin icon off the screen entirely. A new notification popped up in the corner of his monitor: The light in his hallway flickered.