Adrian sat at his desk, typing away on his latest assignment, oblivious to the world outside his headphones.

He was lost in his work, his back to the door, unaware of the world beyond his room.

The intruder slipped in silently, unnoticed, leaving muddy footprints in their wake.

Adrian's mom called out, her voice echoing through the house, 'Adrian, what happened?'

Adrian rushed downstairs, confusion evident on his face. He had been so engrossed, he hadn't heard or seen anything.

The realization hit them like a ton of bricks. Someone had been in their house. The footprints led to nowhere.

Terrified, they ran into the garage, and called the police, the chilling possibility of the intruder still being in the house dawning on them.

The police arrived swiftly, their stern faces a mirror of the situation's gravity. They began their search.

They found no one. The house was empty except for the family and the muddy footprints.

They led Adrian and his mom to his room, and pointed to the message on his door. The officers' faces were grim.

The message was written in Sharpie, a chilling reminder of the intruder who had stood in Adrian's doorway for nearly two hours.

Adrian stared at the message, his heart pounding in his chest. From that night on, he never left his door unlocked.