It is the day after Christmas, and head of Department Q, Detective Carl M rck, is handcuffed in the back seat of a police car headed for Copenhagen's Vestre prison. After 15 years, a violent case from his past, "the nail gun case," has caught up with him, and charges of drug trafficking and murder threaten to destroy his life and career. But he is being framed and someone has a million dollar bounty on his head to make sure he doesn't talk, putting him in grave danger among the prison's incarcerated criminals and corrupt officers. The question that remains is, why?

Carl's colleagues at the Copenhagen Police Department waste no time turning their backs on him, leaving the ever-loyal Department Q team as his only chance. Rose, Assad, and Gordon must go against direct orders from way up the chain to try to unravel the long, intricate threads of the case in search of answers. With only each other to trust and Carl's battle against the unknown mastermind's henchmen getting worse by the day, they must work faster than ever before if they are to exonerate him--and save his life.