Returning to work after being seriously injured, the feisty and determined DC Nina Foster is initially assigned to a desk job to keep her out of harm's way. But as she re-visits the investigation of the infamous 1964 Wickerstead Valley train crash, she finds new evidence that might link that fatal accident to a current spate of heroin-related deaths. Tracking down witnesses, she comes face to face with the notorious Rumbly family and uncovers a network of drug dealers who will stop at nothing to protect their criminal empire.