After receiving a 999 call, North Yorkshire's officers respond to a serious car crash 20 miles north-east of York. At the scene, a middle-aged man is found thrown from an overturned car in a layby at the side of a busy country road on a dark winter's evening.Paramedics and Police fight to save the casualty's life but tragically all attempts fail. With no witnesses to help work out how or why the driver crashed, Traffic Officers call in veteran Crash Investigator - Steve Kirkbright to establish the cause of the collision.When Kirkbright arrives, hypotheses from the officers at the scene seem contrary to the evidence in front of him. Steve discovers the car was travelling in the opposite direction to what officers first thought, losing control and veering across the opposite lane on a bend without any signs of braking. The key question for Steve is why, and could the driver have been distracted or fallen asleep, or was anyone else involved?While Steve returns to the scene in daylight to search for more clues as to how or why the crash occurred, Detective Constable Ed Drake is appointed as family liaison officer. Ed arranges to meet with the deceased's wife to provide her support and learn about his movements leading up to the collision.Near York, PC Paddy Green and Traffic Officers respond to emergency calls reporting a serious crash on the A64. A stranded motorist has been hit from behind by a van driver moments after allegedly being seen reversing up the carriageway.On arrival, Paramedics pronounce the stranded male motorist deceased and officers detain the shocked van driver for questioning.Crash Investigator Paddy and the team begin gathering evidence and testimonies from witnesses to understand whether the van driver was culpable for the death. Should the van driver have seen the stranded car? Was he distracted in some way? Was the car driver reversing back up the carriageway as alleged by witnesses? All key questions Paddy and investigating officers must answer during a lengthy crash investigation which could lead to the van driver facing a crown court trial and a possible prison sentence.