: A ten-second clip. When he played it, he heard only the sound of a heavy door creaking open, followed by his own voice saying, "Who's there?" exactly five seconds before he actually said it. Gift.exe : The icon was a gift box wrapped in barbed wire.

Leo wasn't a man of superstition, but he was a man of curiosity. It was his twenty-fifth birthday, and the sender was a string of alphanumeric gibberish that looked more like a hardware error than an email address. He clicked download. The progress bar crawled, agonizingly slow, as if the data itself was reluctant to enter his hard drive.

The file arrived in Leo’s inbox at 3:00 AM, a jagged anomaly titled "Birthday Gift From Hell092.7z."

: A high-resolution satellite image of his own apartment building. A red "X" was pulsing—not on the image, but seemingly within the pixels—right over his bedroom.