The area under Adventure Mountain is a rarely explored area that is rumored to be a home to the Drow and other various races that prefer life beneath the earth.
The party was led to explore here, tracking down rumors that the person behind the Giants raiding the countryside, Larloch, was located beneath Adventure Mountain. Adventure Mountain itself still proves itself to be too tough of a nut to crack directly.
The party first gained entrance to this area by exploring an icy cold mountain lake located just behind Adventure Mountain. They discovered deep, carved underwater passages that led them to the Underworld Sea. While navigating the sea, the found an island, and from there, they located the nearby beach.