Spencer Marlowe wakes up in a hospital in Chicago, bruised, bloodied, and missing every memory of who he is. Having killed a man. As he grapples with the blank slate his mind has become, he's met by FBI agent Savannah Steele-a fiery, determined woman who claims they've been partners through countless dangerous missions. Despite her efforts to jog his memory, nothing clicks. Soon, Steele has convinced Marlowe to join in a high-stakes undercover operation to take down one of the city's most feared drug lords, Enrique Ramirez.

Tasked by FBI handler Dale, Marlowe and Steele must infiltrate the vast and dangerous 1965 Sturgis rally, posing as a biker and his accomplice. Their goal? To broker a heroin distribution network with America's deadliest biker gangs, all while secretly gathering evidence to bring them down. But when their cover is blown by the ruthless Black Hills Demons, and backup fails to arrive, the pair are forced to rely on their wits, skills, and each other to survive a violent world where everyone's an enemy, and trust is a dangerous game.