Jamie Watson and Charlotte Holmes are looking for a winter-break reprieve after a fall semester that almost got them killed. But Charlotte isn't the only Holmes with secrets, and the mood at her family's Sussex estate is palpably tense. On top of everything else, Holmes and Watson could be becoming more than friends but still, the darkness in Charlotte's past is a wall between them.

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,...