When Frank and Joe Hardy and their friend Tony Prito crash land in a lake in Idaho, they're just glad to be alive. However, they soon learn that the people who live on the town next to the lake are stranded by a washed-out bridge and that one of the townspeople has disappeared. To make matters worse, nearly everyone is blaming their troubles on a lake monster. Frank and Joe are skeptical about that, and they set out to solve the mystery, which turns out to be much bigger than they realize.
22 parts