DEA Agent James Butler is back after apprehending the notorious cocaine kingpin Santiago Rodriguez in New Orleans, Louisiana. He was moved because of the threat to his family and his life. Now it's a new city and a new drug. Music City Nashville, Tennessee. The drug is GBL, Gamma-Butyrolactone. It is sold in elite fitness centers and local gyms across America from the East coast to the West. The miracle supplement, Atomic Blue, is meant to increase muscle mass, heal injuries, and help recover from arduous workouts. Professional bodybuilders, gym rats, and professional athletes consume it. The drawback--The effects were precarious and sometimes fatal—fainting, seizures, and comas that could lead to death. The lethal drug is imported from an unknown location in China. But who manufactures it, and what was so alluring about this "miracle" drug? Butler needed answers. The central hub for the dangerous concoction is in Franklin, Tennessee, from which thousands of gallons of GBL are shipped across the country. The mastermind is Clark Kent, the conniving profiteer. Butler's mission is to obliterate the hub, capture Kent, and stop the flow of GBL out of China. Butler needs the assistance of his colleagues, a group of seasoned agents who will stand in harm's way for each other. It will take every bit of their expertise to dismantle the GBL trafficking network and "pull the curtain up" on the blackout in Music City.