A number of sheep has been savaged or killed, and Inspector Crossley is convinced that a very big cat like a puma is at large in the area. To Blaketon it looks more like the workings of a dog and Greengrass' lurcher Alfred seems to be the culprit. Kate Rowans starts in her new job at Dr. Radcliffe's surgery in Whitby, although she feels as if she is being kept outside deliberately. Not by Dr. Radcliffe himself, but by his receptionist Christine Ferguson. Meanwhile Greengrass has settled his outstanding account with the Inland Revenue in his own, very unique way.

Young Jamie Halsted is camping out with he parents. He is very sad because his dog Sam is missing, and when a man dies of rabies Sam gets under suspicion because Jamie's father is a former army major, who has been stationed abroad, and Blaketon organizes a major search for the animal in order to stop the disease from spreading. There's a new police car in town, and PCs Rowan and Ventress take it out for a spin. It has been some time though since the last time Alf Ventress was behind the wheel.

PC Rowan gets assigned to special duty with the CID in Whitby. He will be investigating reports of smuggling among the local fishermen. Ventress is asked to help him, but unlike Rowan he has to pay all expenses by himself since he is on holiday. Rowan's main suspect is Cedric Shanks, but to get close to him Rowan needs the help of young Jake Stirling, who is in dire need of a job because he has gotten his girlfriend Liza pregnant. Blaketon takes over Rowan's patch while he is away and uses the opportunity to keep an eagle eye on Claude Jeremiah Greengrass.

Believing he has killed his captain in a brawl the Russian sailor Vladimir Ivanov makes himself scarce and asks PC Rowan for political asylum. But Ivanov does not trust immigration officer Fillingham and clears out once again during transport to the immigration office in York. To satisfy his hunger he steals the lunch of Dr. Radcliffe's daughter Jennifer, who is on a field trip with her class. Jennifer wanders off with her friend Dennis and follows the Russian with a childish notion of catching him and become heroes of the day. Sergeant Blaketon starts a big search for both the Russian and the two children.

Ron Cooper is an old army veteran with enough illegal weapons, ammunition and explosives to run his own militia. He gets injured when a rifle backfires and is taken to hospital. Unknown to him four boys have found his collection and they "borrow" a box of ammunition not knowing how dangerous it is. Furthermore Greengrass buys some hand grenades from Cooper's helper Morris and cleans out lord Ashfordly's entire stock of trout. Meanwhile Kate Rowan's work at Radcliffe's surgery in Whitby is taking its toll on their marriage and they start to drift apart, when Kate discovers that she is pregnant.

Ronald Pitts wants to buy Tom Abbott's farm, but the old man does not want to sell. One morning his sheep have been let loose. Furthermore Kate Rowan suspects that there is brucellosis on his farm, because a young girl, Jane Shields, has caught the disease apparently by drinking unpasteurized milk from one of his cows. Greengrass is going to church. He has not become a holy man though, but he tries to get a reward for finding a lost heir and wants to look into the church records. PC Ventress still has not quite got the hang of driving. On a nightly patrol he parks his police car in the middle of a river trying to avoid a flock of sheep on the road. When he leaves the car to get help he hears an eerie scream.