MULDER JUMPS IN WITH BOTH FEET WHEN A MISSING PERSONS CASE IN GEORGIA TIES IN WITH AN OLD AND PERSISTENT LEGEND OF A LAKE-DWELLING MONSTER. SCULLY REMAINS SKEPTICAL UNTIL AN ACCIDENT STRANDS THEM IN THE MONSTER'S TERRITORY IN THE DEAD OF NIGHT.
Scully can hardly believe that even Mulder would be gullible enough to take on a Nessie-type lake monster legend when a Federal Forest Service worker is killed along a lakeshore in Georgia. They find that the area has been experiencing a "frog holocaust", a steady and disastrous decline in the native frog population. The local fishing and boating population begins to decline as well, with parts of bodies turning up in remote areas. Mulder pleads with the local sheriff to close the lake to tourists. Scully is more inclined to believe in a human serial killer, but when her beloved dog gets involved in the hunt and people are attacked before their eyes, she joins Mulder in tracking down the prehistoric creature who is feeding on the locals. They find themselves trapped in the middle of a fog-shrouded lake, with something very, very big closing in on their position.