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.

During a dinner at Ashfordly Hall the county High Sheriff Andrew Parkin makes a pass at Susie Cope, who is serving at the dinner. On their way home from the dinner Parkin and his wife Sonia run down the farmer Colin Taylor. The Parkins claim that Mrs. Parkin was driving the car due to him having too much to drink, but PC Bradley is not sure because the driver's seat was too far back for her. Either way the accident may turn out to be a costly affair for the Parkins, because their insurance does not cover her driving the car. Furthermore Susie Cope tells Oscar Blaketon, who is acting as a private investigator on Taylor's behalf, that she is certain that it was the High Sheriff himself who was behind the wheel. Vernon Scripps revives an old idea of his, a marriage bureau.