This episode explores in depth the fascinating history of lake Champlain, from its natural history to the history of human beings living by the lake as well as a detailed look into the origins of Lake Champlain monster sightings in the past few hundred years. Included are theories about the monster as presented by the foremost "Champ" investigators.

Episode 2 deals with various eyewitnesses of the Champ monster and their highly detailed testimonies of their encounters. Aside from numerous eyewitness interviews there is an examination of the various pieces of alleged Champ monster videos and photographs taken over the years, including the infamous Sandra Mansi photograph from 1977.

Primeval Champlain explores the darker depths of the lake and swampy marshes alongside the Mardis-Dranginis Lake Champlain Research team, as well as Katy Elizabeth of Champ Search, each team showcasing their research approaches. Included is an interview with a witness who recalls the extraordinary Champ monster sightings that have taken place over the years near the mouth of Winooski River.

Champ Search follows Katy Elizabeth of "Champ Search" as her team searches various corners of the lake both in the daytime and at night, from deploying a scuba diver in the depths of Arnold's bay to utilizing audio equipment to monitor for echolocation to researching during the winter months.

Episode 5 deals with the local communities surrounding Lake Champlain and their relationship with the lake, but more broadly with the Champ monster as a cultural phenomenon. Discussed is Champ as a local mascot, the various ecological threats facing the Lake and the future of Champ research and what that may hold for the lake.