The plot finds Nancy, Bess, and George investigating a mysterious boy from India. The boy, Coya, works for a traveling circus, and is treated poorly by his guardian, Rai, who is in charge of the circus, who is also a native of India. Coya runs away from his abusive guardian and seeks asylum at the Drew home in River Heights. Soon after his arrival, the girls begin investigating property owned by the unusual Mrs. Anita Allison. They encounter a house "with no insides," and a hidden tunnel. The property mysteriously catches fire, revealing a hidden cache of jewels. Nancy traces Coya's parentage and uncovers a sinister kidnapping plot involving both Mrs. Anita Allison and Rai. The climax also reveals a secret about the ivory charm, and its mysterious powers.