The next year, he travels (in "Clouds of Witness", 1926) to the fictional Riddlesdale in North Yorkshire to assist his older brother Gerald, who has been accused of murdering Captain Denis Cathcart, their sister's fiancé. As Gerald is the Duke of Denver, he is tried by the entire House of Lords, as required by the law at that time, to much scandal and the distress of his wife Helen. Their sister, Lady Mary, also falls under suspicion. Lord Peter clears the Duke and Lady Mary, to whom Parker is attracted.