Plot Summary:Scully and Mulder are called in when a businessman is found dead in his office. The doors and windows were locked from the inside and the only other possible opening is an extraordinarily small air vent, which no person could possibly go through. The dead man also had his liver torn out. There is also a strange elongated fingerprint on the vent which leads Mulder to find two sets of old cases the first dating to 30 years ago and the other 30 years before that. All of the victims had their livers torn out of their bodies. More importantly, the elongated fingerprint is an exact match, despite the long interval in between events. Mulder is convinced that the killer is the same man who comes out of hibernation every 30 years to feed his appetites.