Moonshiners Mark, Tim, and Josh drive the notorious Thunder Road in Dawson County, Georgia, to investigate the murder of "Lightning" Lloyd Seay, a notorious bootlegger turned pioneering stock car racer who was killed over a few bags of sugar.

Mark and Digger spot their liquor thief on camera as Tickle, Josh and Henry strike gold in Philadelphia with their Peach-Rye recipe. Mike adds insult to injury when he buys out Mark Rogers' sugar supplier, pushing the backwoods shiner to the brink.