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.

Danger abounds for the Hardys as they search for the culprit of several burglaries, computer thefts, and threatening messages inflicted on Cody Chang's San Francisco shop, Skin & Bones.

The Hardy Boys are threatened at a combat sports training center.

The Hardy brothers embark on a freighter trip under mysterious circumstances and find themselves involved with a smuggling ring.

Participating in a motorcycle exhibition, the Hardy boys must solve some suspicious accidents before the race ends in a disaster.

The Hardy boys, trying to keep things in line during the Merchant Association's Halloween mystery contest, contend with spooky settings, fright-masked bandits, a chase through the Halloween parade, and a horror movie star with secrets buried in his past.

Having been given press passes to cover the Indy Formula One race, Frank and Joe Hardy find they are under attack when they attempt to solve the mystery of the competition between the top two racers.