London policeman Nick Rowan and his recently qualified Doctor wife - Kate move away from the city and go to the rural surroundings of Aidensfield, a village in the heart of the North Yorkshire Moors, where Nick's the new village policeman. Whilst they are still settling in, Nick's new section Sergeant, a Sgt Blaketon calls for Nick and takes him to see the local Rogue - Claude Greengrass and insists that he charge him with livestock worrying after his dog, Alfred killed a budgie! Greengrass admits Alfred did kill the bird and offers compensation, but Blaketon insists Greengrass be charged, despite Nick's reservations. The case goes to Court, but due to insufficient evidence, the court can't charge Greengrass as a budgie isn't classed as livestock. Meanwhile a local woman, Georgina Fraser tells Nick that she has a prowler at her house and one night she calls Nick out when the prowler returns. She then see's him at the village pub, the Aidensfield Arms, and Nick goes to see the Landlord

There is to be a big CND demonstration outside the Fylingdales early warning defence base near Aidensfield, and prospective MP - Paul Melthorn is to make a speech there. Workers take offence when demonstrators are putting up posters everywhere advertising the demo and Nick has to break up a row in the pub between them. In doing so one of the demonstrators gets injured and Nick gets accused of assaulting him. Ashfordly police in the meantime are informed to police the demo and Blaketon finds out that the American Ambassador is visiting Fylingdales at the time of the demo. The demonstrators campsite is then burgled and Melthorn's wallet, which contains incriminating pictures of him having an affair with a young woman are stolen. The demo takes place and the road is blocked with demonstrators. Melthorn makes his speech but becomes ill and Kate arrives to treat him and discovers he has a weak heart. It turns out that the demonstrator who accused Nick of assault is in fact a Special Branch