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

Embarking on a class trip to Bayport Bear Park, Frank and Joe join in an exciting scavenger hunt before learning that the prizes slated for the winning team have been stolen or destroyed by an unknown culprit.

Frank and Joe are brothers, but that won't stop them from competing against each other at the Fun World arcade's video game tournament. The boys make a bet: Whoever wins the competition gets to move into the cool new room their dad just built! But suddenly money goes missing. The owner of Fun World shuts down the tournament until the stolen cash is returned! Can the boys figure out who took it? Or will their chances of victory -- and a brand-new room!...

The Hardy brothers' search for the missing son of a wealthy industrialist leads them to Brazil and great danger.

Valuable electronic parts containing platinum are being stolen from shipments made by Stanwide Mining Equipment Company's cargo planes, and Frank and Joe Hardy are called upon to assist their world-renowned detective father to solve the baffling case. At Stanwide the boys pose as employees, and become suspicious of their boss's hostility toward them. Is he involved in the racket? And what is the truth behind the plane crash at sea in which Clint Hill,...

Young Frank and Joe Hardy enlist the help of their friends to solve a mysterious case involving a large number of frogs.

Teenaged detectives Joe and Frank Hardy uncover a plot to sabotage a ski resort.

Determined to learn the secret of the old mill, Frank and Joe employ a clever ruse to gain entrance and become trapped. There they unravel two mysteries, one involving a counterfeiting case and the other a national security case about the missile parts that their father is working on.

Right before the final game of the Little League season, the Bayport Bandits' lucky charm--Jason's mitt--goes missing! The team is devastated. Can Frank and Joe solve the case of the missing mitt before the Bandits lose the game?

When the Hardy boys reached the caves, they came unexpectedly upon a queer old hermit.