Lovely young Carla Ponce, a resident of Peru, invites Nancy, Bess and George to visit her and solve a mystery that promises to lead to a fabulous treasure. A clue is carved on an intriguing wooden plaque belonging to Carla’s family. When a notorious gang headed by El Gato steals the priceless relic, Nancy quickly recovers the old plaque. Through clever deductions, perseverance, and dangerous adventures, Nancy and her friends help to capture a ring of vicious smugglers and make an astounding archaeological discovery.
