Retired police officer Luke Fitzwilliam was traveling by train to London. En route, he struck up a conversation with a fellow traveler, an elderly lady named Pinkerton, and discovered she was going to Scotland Yard to report a series of murders committed in her town of Wychwood-under-Ash. Luke, secretly laughing at the impressionable provincial woman, didn't believe a word she said. However, he was forced to reconsider when he learned some time later that Miss Pinkerton had been hit by a car. Luke traveled to Wychwood to investigate the case. But he would hardly have succeeded in this challenging task if Superintendent Battle hadn't stepped in.