Why is a wealthy sportsman so frightened by the serpent design on a mysterious balloon that he begs Frank and Joe Hardy to protect him? And who stole the ancient, life-size chess king which is to be presented to the winner of the world chess championship? These questions and others equally as baffling in this exciting mystery seem to defy explanations. On the ground and in the air Frank and Joe find themselves the targets of diabolical enemies. An odd clue that they discover leads them across the Pacific to Hong Kong. There the young detectives match wits with their adversaries. How they help the police smash an international criminal organization provides an electrifying climax to one of the most challenging cases the Hardy boys have ever tackled. - Flyleaf.