 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.