A seasoned private investigator answers an urgent appeal from a fellow sleuth and becomes embroiled in a sprawling case that shifts from city streets to remote hills and border country. The plot proceeds in episodic set pieces that include robberies and further murders, secret orders, changed identities, explosives, and a recurring emblem that connects scattered clues. Allies and rivals each affect the investigation as the protagonist confronts hidden dungeons, caves, cliffside pursuits, and a deaf-mute witness while piecing together evidence. The work alternates deduction with fast-paced action, testing perseverance and ingenuity.