When a young woman is fatally mowed down by an out-of-control car, it's thought to be a tragic accident - the driver having apparently died behind the wheel. But as evidence suggest the driver was dead hours before the accident, Allie and Duncan find themselves investigating a mysterious double homicide.

Allie and Rhys investigate the brutal death of a charity worker and as their investigation unfolds they discover a revenge motive stretching back over 25 years. Meanwhile, Stanley tries to make a traffic violation go away for his daughter Stephanie but the arresting officer doesn't make things easy for him.