"Deep in the forbidding Alaskan wilderness is an area swathed in mystery. There are two bottomless lakes where people have been vanishing without a trace for thousands of years. The extreme angler searches for the lethal lake monster of native legend that is dragging locals down to an icy grave. Sub-arctic fishing is a first for Jeremy and ends up with him landing the largest fish he has ever caught... but is it the monster?"
Deep in the Alaskan wilderness, Lake Iliamna is supposedly the home of a monster. Reports claim it grows 20 feet long and is responsible for the disappearance of many fishermen. Investigating the identity of this creature, Jeremy faces cold-water fishing for the first time during the series. He investigates the possibility of the monster being a pike or a beluga whale, but none would match the description.
Wade then tries to find out a possible food source: salmon. This results in the first salmon he has on the end of his line, only to have it stolen by a bear. After hearing an eyewitness' encounter, Jeremy is able to determine the identity of the culprit: a white sturgeon.
These fish grow to 20 feet long and are known to leap out of the water, which could result in people going missing. Fishing for sturgeon, Wade soon faces what may be the biggest fish he's ever caught (although this episode was shot before "Death Ray", which features his biggest catch in this season).