Midsomer Murders, an English crime drama series based on books by Caroline Graham, is filmed mostly in the villages and towns of the rural counties of Buckinghamshire and Oxfordshire. John Nettles plays Chief Inspector Tom Barnaby of the Causton C.I.D., a laconic, down-to-earth detective who faces many ingenious and remarkable murders (usually several in each episode) amid the eccentric denizens of Middle England. For the first twenty-nine episodes Barnaby's partner in detection was Sergeant Gavin Troy, played by Daniel Casey. Troy was then replaced by Sergeant Dan Scott (John Hopkins), who again has been replaced by yet another Sergeant (we first meet him as a DC, Jones, played by Jason Hughes. Other regulars include Tom's wife Joyce (Jane Wymark) and his daughter Cully (Laura Howard) , who sometimes get mixed up in the plot