The robbery of the treasure in the tower proves to be an exciting challenge to Frank and Joe.

"The Secret of the Old Mill" is the third installment in the "Hardy Boys" series of mystery stories. Written by Canadian author Charles Leslie McFarlane and published under the pen name, Franklin W. Dixon, in 1927, "The Secret of the Old Mill" ranks as one of the best books in the series. In this thrilling installment, readers find the Hardy brothers, Joe and Frank, investigating the mysterious appearance of counterfeit money in their small town of...

Teenage detectives Frank and Joe Hardy investigate a supposedly haunted house reported to be the hangout of criminals.

Hired to locate an old Spanish cannon, the Hardy brothers uncover an even greater treasure after perilous underwater adventures.

False robbery charges, Joe's disappearance, and other strange things occur when Frank and Joe set out to retrieve their father's important papers from a diver.

The two Hardy brothers help their father search for stolen electronic parts.

When two suspicious plane accidents occur near an eastern airport, the two Hardy brothers investigate the case and find themselves in greater danger than they anticipated.

While searching for the guard end of a broken saber that will solve one mystery, the Hardy brothers become involved with a gang of bank robbers.

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