After a dying criminal confesses that his loot has been stashed "in the tower", the Hardy boys make an astonishing discovery.,

When the Hardy boys buy a Chinese junk for a money-making venture, they discover it has a serious flaw.

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.

When the Hardy Boys set out to solve the mystery of their missing chums, they discover a gang hide-out in a cave on an island along the way.

Collects six adventures featuring Frank and Joe Hardy, who use their detective skills to investigate mysteries, help their friends, and bring criminals to justice.

The Hardy boys dial a wrong number, get the Pentagon, and suddenly find themselves in a dangerous adventure involving national security.

Helping in a case their father is working on, the Hardy brothers try to find an informer who has telephoned from a booth in their home town, and are hired by a carnival owner to spot pickpockets.

Vicious threats and deadly traps beset Frank, Joe and Chet as they search for clues to the stolen paintings and the gold treasure--a search that is complicated by a stormy feud between a proud Englishman and an equally proud Franchman over the military history of the ancient fort.

The Hardy boys embark on another puzzling mystery when they try to discover who is stealing rare collections of ancient pirate treasure and smuggling them out of the United States.

Frank and Joe solve a mystery involving the disappearance of a professor, a hot-tempered hermit, sabotage at the station, and the Honeycomb Caves.