Billy the new sniffer spaniel finds live ammunition during a search for drugs, and a stabbing on the streets of London brings together two of the city's leading Alsatian dog teams. PC Mandy Chapman and her canine companion Karly are sent in to enforce a court warrant against a dangerous dog, while Sergeant Peter Madden and Brodie are on the trail of burglars using stolen cars as getaway vehicles. Narrated by Ken Stott.