The search for a stolen boat leads the Hardy brothers to Mexico where they become involved with a band of Indians and a strange smuggling operation.
Frank and Joe investigate a walled estate guarded by savage dogs, where a businessman is hiding in fear of his life.
The Hardy boys and two friends take a camping trip to the Rocky Mountains in an attempt to locate a gang of credit-card counterfeiters.
Once again Frank and Joe Hardy accept the challenge of a puzzling case when their famous detective father asks the boys to assist him in tracking down a notorious jewel thief and his accomplices.
