Frank and Joe Hardy become involved in a large and dangerous conspiracy while trying to keep the valuable invention created by one of their father's clients from falling into the hands of thieves.
When Frank and Joe try to get hold of a top secret invention, they are put on the trail of jewel thieves and smugglers. Joe is kidnapped and Frank starts off on the chase.
Frank and Joe Hardy become involved in a large and dangerous conspiracy while trying to keep the valuable invention created by one of their father's clients from falling into the hands of thieves.
When their detective father asks them to play burglar in order to protect a client's valuable invention from thieves, the Hardy boys find themselves involved in a large and dangerous conspiracy.
