Josh Roberts is a first class vet, but he also has developed a drinking problem after his wife's death and is almost always drunk. He forces sergeant Craddock off the road one night and Craddock orders his constables to be on a special lookout for drunken drivers in general and Roberts in particular. That does not scare off Roberts, who considers himself safe because he is the only vet in the area and he stages his own little, private war against the sergeant. There is a country fair in Aidensfield and Greengrass sees yet another opportunity to earn a quit or two and opens a stall just outside the fair and leaves David in charge. And he has some real bargains. Especially the sheep skin rugs! Phil tries to make a good impression on Sue Driscoll, the new secretary at the Ashfordly police station.

Vernon Scripps and David are on their way in a tanker when they are forced off the road by an oncoming car. None of them get seriously hurt when the tanker overturns, but Vernon Scripps has a temporary loss of memory. Dr. Alway gets him admitted to his own hospital The Royal in Elsinby. The contents of the tanker ooze out on the ground and into a river and several people show signs of poisoning. Vernon Scripps is the only one, who knows what is in the tanker, and the hospital staff will not let anybody talk to him. Getting the tanker contents analyzed will take days and meanwhile nobody is allowed to use the tap water.

Everybody is shocked over Phil Bellamy's death, and especially his wife Gina cannot believe he is gone. After the funeral she says she has decided to go back to Liverpool to make a clean break from the past. Headquarters has agreed to let PC Mason stay in Aidensfield, and PC Wetherby, who blames himself for Bellamy's death, fills the vacancy at the police station in Ashfordly. A teacher from Brassington School on the moor is found dead in his home after an apparent suicide. From his headmaster Anthony Barlow PC Mason and DS Dawson learn that he suffered from a depression over the death of one of his pupils on a school trip, but Mason is sure something is not right. Unaware that he nearly hit a cyclist with his car old Arthur Chiltern drives on, but the cyclist Dr. Oakley wants him charged with reckless driving. Nurse Cassidy tries to persuade him to drop the charges. She succeeds with something else as well when the handsome doctor asks her out.