You are John Raimi, a disease-control agent with the federal government, on loan to an elite counterterrorism unit. Your team is sent to investigate the shadowy Volks Corporation. When the operation goes horribly wrong, you are captured and subjected to a ghastly experiment that rips your spirit from your physical body. You now roam the halls of the Volks Corporation compound as a spectral phantom, using your powers to scare and possess any human or animal that crosses your path.
If you're going to have any hope of finding your own body, you must employ your hair-raising power of possession to control humans, animals and objects, using the unique abilities of each to explore the compound, solve puzzles and strike at your enemies. Along the way, you must discover the secret of the Volks Corporation to unravel the mystery of your condition and find a way to recover your human form.