The Hunniwell boys and the platinum mystery

"The Hunniwell boys and the platinum mystery" by L. P. Wyman is a juvenile aviation adventure novel written in the early 20th century. It centers on brothers Bill and Gordon Hunniwell and Secret Service agent Steve Rogers as they pursue a century-old clue to a hidden cache of precious metal in the Hawaiian Islands. Flying their experimental electric plane, the Albatross, they combine sleuthing with daring flight and face shadowy opposition around Molokai’s rugged cliffs. The opening of this novel follows the boys from a Maine fishing trip to a visit by Rogers, who reveals an 1816 attic letter and map hinting at a stash of metal impervious to nitric acid—likely platinum—hidden on Molokai. They agree to search for it, depart in the Albatross, and make a cross-country-and-Pacific flight marked by a thunderstorm, a ghostly mail-plane encounter, and a close pass over a whale before fog forces a blind landing on a beach. After resupplying in Honolulu, they camp near Laau Point, hear an eerie night wail, and begin searching sea-cliffs between tides. Their battery cells are stolen, but they track down a Japanese thief and recover them; later, someone tries to crush them with a rock from a rift above the shore. Deciding it’s unsafe below the cliffs, they reconnoiter from the air and keep guard—until Gordon vanishes from camp. Finding the plane’s motor brushes removed, they fit spares, take off, and finally spot a hidden hut in a dense thicket, where the opening section breaks off.