Treasures of antiquity, long hidden in the sea, yield at last to modern electronic inventions when Rick Brant, his pal Scotty, and Chahda, the Hindu boy, share another hair-raising adventure –– this time in the far Pacific, off the tiny island of Kwangara.

     Under the leadership of Rick's father, a famous scientist, the members of the expedition set out with their astonishing invention, the Submobile, in which they hope to conquer ocean depths as yet unplumbed and bring to light traces of a civilization hidden for centuries under 100 fathoms of water.

     But the irresistible lure of sunken treasure causes treachery in the crew, and age-old superstitious fear brings to a head the hostility of the island natives. Caught between these two forces, Rick and his friends find themselves facing danger equally as imminent as that of the terrific atmospheric pressure which constantly threatens their Submobile.

     Packed with action, suspense, and excitement, here is a story that is well equipped to take its place with The Rocket's Shadow, The Lost City, and Sea Gold.