Alec Formby and his fiancée Sonia Harding are on route with a radioactive isotope to a laboratory in Leeds and make a stop at the Aidensfield Arms to get something to eat. When they have finished their car has been stolen. The Police recover the car again after it has been involved in an accident, but the lead bottle containing the isotope is gone. Greengrass' brother Cyril calls on him with a business proposition He has bought a racing dog and needs a place to keep it for a couple of days. The dog is very fast and Greengrass races the dog without his brother's knowledge.

With no village bobby in Aidensfield Tommy Unsworth and his motor biking friends seizes the opportunity to make a lot of trouble in the village. Even Aunt Peggy is upset that the bikers are trespassing on Lord Ashfordly's land upsetting the natural order of things by frightening the game away and leaving her traps empty. But when it will take a while to get at permanent replacement Miller organizes a stop gap. Thus PC Joe Mason moves to Aidensfield on a temporary basis while he awaits his transfer to the Met. Mason is very resourceful and a bit of a maverick, and his senior officers were more than happy to get rid of him. The villagers are not too crazy about him either. But Unsworth is not the only source of trouble around. A professional gang from Manchester is targeting country houses in the area stealing paintings, antiques and jewelery.