Teenage "joy-riders" mow down a young man on his way home after a night out with his mates. As he fights for his life in hospital, the police struggle to find the culprits. Expert tracker dog, PD Q, follows a scent from the abandoned car, but it leads to a dead-end. Where is the driver of the stolen vehicle? Could this incident be the culmination of a sequence of escalating attacks on participants in Oxford's Pride Parade? DCI Jonah Porter steps in to find out.