One morning, however, disaster strikes. Happy Horse slips in the shower and breaks one of his splendid teeth. Will he ever be able to smile again? Happy Horse disappears and everyone is very worried. His friends soon rally round to find out what's wrong. Luckily, clever Daft Dog knows just how to bring back Happy Horse's cheery grin - a trip to Mr Gnasher the dentist. But - oh dear - Happy Horse is terrified of the dentist - what's to be done?