At the Almanarre Cup windsurfing championships Frank and Joe investigate a strange series of "accidents" that threaten to put Doug Newman out of the competition.

The Hardys must find out who is trying to put Zack out of action at the first annual Thrashathon.

Frank's girlfriend, Callie, is the star of the show, but someone has threatened to make this the last part she ever plays unless she finds the missing prop, a tiara that has been stolen.

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,...

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

In response to Nancy Drew's cry for help, Frank and Joe Hardy race to the mountains of the Wyoming wilderness where a million-dollar criminal enterprise has cut off a mountain expedition of which Nancy is a member.