Frank and Joe go to the Pocono Mountains to investigate the mystery of a legendary witch who stalks Black Hollow seeking vengeance. Disappearances occur and strange screams fill the night.
Frank and Joe Hardy search for clues to solve the mystery of the Beast-o-matic, which crazy inventor Mike Mendez has apparently used to turn their friend Chuck into a dog.
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.
