After the epic horrors of DOOM and The Beginning of the End parts I and II you are a broken man. Demons haunt your mind and plague your sleep. Unable to cope, you are sent to a UAC medical facility that also happens to double as a radioactive toxic waste treatment plant. Here, along with the few other surviving scarred space marines, you are prescribed cryno-therapy. Your body is placed in suspended animation while your mind is flushed with chemicals and stimulants in order to cleanse the horrors from your psyche. But something is wrong. As soon as you are put into stasis, you awaken again. Things are different. The building seems deserted and in shambles. No sounds are heard. You step out of your chrinochamber to a familiar smell. The smell of rancid flesh. The smell of death. You draw your pistol, which you never let leave your side no matter what the circumstances. You wonder if this nightmare will ever be over. You get the sense the worst is only beginning.