Ken and Harry are guarding Tinkerbell, a greyhound, at Woodcote Park, before her big race. The owner, Mr Hancock, insists that Tinkerbell must be fed ""Mr Marrow"" dog food and a detailed record must be kept of how much of it she eats. Harry gets Rocky to feed and walk the dog, and it soon becomes clear that Tinkerbell hates ""Mr Marrow"". An attractive blonde woman turns up at Woodcote, deliverin...