According to the blurb: "Bat Scanlon, two-handed fighter and trainer, is worried. He visits an old friend in his big country house, and runs into some queer things he cannot explain - the thunder that rumbles over the hills when skies are clear - the harp that is played without sound, enemies without - and a traitor within the house. Bat calls on Ashton-Kirk, who has solved some strange mysteries, and a special detective comes to grapple with the terror."