A 52-year-old cyclist has died after being knocked off her bike by a white van as she raced on a dual carriageway near Raglan in Monmouthshire. She was just nine minutes into a time trial with a group of other competitors when her ride was cut tragically short. With the van driver now under arrest and facing serious questions, Sergeant Cath Raine has been called in to investigate the final moments of the cyclist's journey. But the collision has happened on a concrete road, with barely a trace of evidence on its surface – and she knows that even a single mark could hold the key to justice. So when she finally discovers a clue at the edge of the carriageway, it raises more questions than answers.