If you were to look into the depths of Apeture Laboratories, given that you could slip past GLaDOS, you'd find a sturdy, worn, metal door. If the heavy locks aren't enough to discourage you from prying, the many signs plastered on it should-
a few reading 'Defectus', 'Keep Out', 'Do Not Enter', 'Inhumanum Experimentis', 'Conversus', and 'Reiciet'. Why are these signs here, you ask? And on this specific door? No-one knows- the only one that bothered with it once was GLaDOS, and has never spoke of it since. The other robots of the facility never bothered to look behind it, if only in fear of the ominous signs, and what punishment from whatever may lay beyond if there was a breach. The sounds of creaking and groaning always came from beyond the door, sometimes shrieks of pain, followed by eerie silence- active machinery was another sound that invaded the air around the door, adding to the creepyness of it all. None of the inhabitants knew what was trapped behind the door, and if they were lucky...

...it was going to stay that way...

A/N: My first attempt at a Portal fanfic- let me know how I did! (this is only the prologue, by the way)