Tom Swift and His Subocean Geotron Author:Victor Appleton II The young scientist-inventor embarks on one of the most challenging missions of his adventure-packed career. The mission: recover a valuable cache left on earth thousands of years ago by colonists from another planet. Can Tom locate it before his deadly foe the Kranjovians seize the capsule? clues to the cache lead him to a location beneath t... more »he ocean floor - near strange Easter Island, with its eerie ruins. Further search is impossible until Tom can invent and build a manned, burrowing mole-mobile - the Geotron.« less