A SERIAL KILLER WHO RIPS HIS VICTIMS' LIVERS OUT WITH HIS BARE HANDS ALERTS MULDER AND SCULLY TO A CRIME SPREE STRETCHING BACK TO THE TURN OF THE CENTURY.
Scully is called in on a locked-room murder mystery by an old FBI Academy classmate who resents Mulder's intrusion into his case, but Mulder's discovery of a strangely distorted fingerprint links the case to other similar cases dating back generations. Scully, working from a psychological profile of the killer, stakes out the crime scene and catches Eugene Victor Tooms crawling out of an air duct. A lie detector test seems to clear him, however, and Tooms is released -- despite Mulder's insistence that Tooms is a 100-year-old serial killer. Their research, plus an interview with a retired detective, convinces Mulder that Tooms is a mutant, a cannibal who can hibernate for 30 years at a time and distort his body to crawl through tiny spaces. Another murder is committed, again inside a locked and shuttered house, and this time Scully and Mulder go hunting Tooms. They find a deserted apartment building, a strange nest in the basement and a collection of trophies, but no Tooms. Scully, only half convinced, returns home unaware that Tooms has targeted her for his final victim, and Mulder must race to save his partner from being eaten alive.