TV presenter Sophie Morgan was left unable to walk after a car accident in 2003. She's on a mission tonight, to find out why traffic collisions are the single biggest killer of young people and, more importantly, what can be done to stop them. Sophie meets people who have had their lives changed in a instant, drivers who race illegally, and a family who were left devastated by a road traffic accident. Finally, she comes face to face with the passengers she could have killed, and takes a long hard look at her actions on the night she crashed.