Fiennes stared. ‘But look here,’ he cried; ‘how do you come to know the whole story, or to be sure it’s the true story? You’ve been sitting here a hundred miles away writing a sermon; do you mean to tell me you really know what happened already? If you’ve really come to the end, where in the world do you begin? What started you off with your own story?’ Father Brown jumped up with a very unusual excitement and his first exclamation was like an explosion. ‘The dog!’ he cried. ‘The dog, of course! You had the whole story in your hands in the business of the dog on the beach, if you’d only noticed the dog properly.’ Fiennes stared still more. ‘But you told me before that my feelings about the dog were all nonsense, and the dog had nothing to do with it.’ ‘The dog had everything to do with