William and Sam are West Highland Terriers who love living at home with their family. When the whole family visit Molly and Fred's farm for Lewis's twelfth birthday, William and Sam are told to be on their best behaviour.

William's sense of adventure lands the dogs in constant trouble with Jimmy, the intimidating farm dog.

All William wants to do is to show Jimmy that he will be a fantastic farm dog, but will William leave the farm unscathed? Or will he meet his match with the most terrifying farm animal of them all?