"Stella looks at the blade," the voiceover whispered in Polish. "Just as Marek looks at the cold cup of coffee on his desk."

The voiceover gave one final narration: "Marek reaches for the door, but he realizes too late—he is no longer the viewer. He is the subfolder."

Marek froze. He looked down at his desk. The chipped ceramic mug was right where the voice said it was. He tried to pause the video, but the spacebar was dead. He reached for the power cable, but the voice continued, louder now.

On screen, the stranger, Giulio, turned away from Stella and looked directly into the camera. The 720p resolution was grainy, yet his eyes were piercingly clear.

The file size in the folder window began to grow. 1.4 GB... 2.2 GB... 50 GB... It was consuming the data of his hard drive, his surroundings, his reality.

"Marek wonders if the 'K' in the filename stands for a name. It stands for 'Klucz.' The Key."