Join Dr. David Throckmartin on a thrilling scientific expedition to the mysterious South Sea Islands, where he uncovers ancient ruins and a portal leading to Muria, an astonishing underground realm. When Throckmartin, along with his wife and two companions, mysteriously vanish, his old friend Dr. Walter Goodwin embarks on a daring rescue mission. As he ventures into Muria, he encounters a breathtaking world filled with incredible beings, remarkable scientific innovations, and the ominous worship of the most malevolent creature of all The Dweller. (Introduction by Mark Nelson)