The fourth in the comedy series featuring comedian Jim Varney as Ernest P. Worrell. Out searching for treasure one day with his metal detector, Ernest discovers an ID plate from an old war cannon. Together with his mate Abner, Ernest goes in search of Goliath - the largest cannon ever, from the American war of Independence. According to legend and Abner's theories, the cannon contains the real Briitish crown jewels. However on the treasure trail also are a gang of crooks. Cue mayhem.