The robbery of the treasure in the tower proves to be an exciting challenge to Frank and Joe. Frank and Joe attempt to foil a ruthless espionage ring in their effort to sabotage the United States space program.

"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...

Frank and Joe Hardy search a mysterious castle for clues to a stolen, extremely valuable comic book.

Detective brothers Frank and Joe investigate garden sabotage.

During the the annual "Fun With Camping" event at Bayport State Park, Frank and Joe investigate when tent decorations start to go missing and they find mysterious footprints around the camp.

When television wildlife celebrities Jumpin' Jack and his son bring their menagerie to Bayport Elementary, Frank and Joe are on the case for a boa constrictor that goes missing.

While on a cruise with their family, Frank and Joe investigate the theft of former pop idol Izzy's pocket watch.

When a sinkhole opens up and swallows one of Bayport?s historic statues, Frank and Joe suspect something?or someone?shady at play. They jump at the chance to investigate; Joe as a member of an urban exploration club, and Frank as photographer for the school paper. But in the thick of their search, the boys stumble upon an entire underground city that?s been abandoned for years. Now the city is home to a cultish band of criminals who plan to take over...

The Hardy boys and their father solve a mystery involving inexplicable crashes of high speed race cars being used to test an experimental turbine motor.

A series of bizarre events in their home town lead the Hardy Boys on a trail of robbers and kidnappers.