Wilma Tenderfoot, a ten-year-old orphan who lives at Cooper Island's Lowside Institute for Woeful Children, dreams of escape and of becoming the apprentice of the world-famous detective Theodore P. Goodman, whose every case she follows devotedly in the newspaper

When Wilma Tenderfoot, the feisty and determined assistant to the world's greatest living detective, and her beagle Pickle, find a mummified body buried on the grounds of the gothic mansion Blackheart Hoo, they seek to identify the body and solve the mysteries of a key, some buried treasure, and a kidnapping