40,000 years ago, deep within the awesome Subrano Caves of Yugoslavia, a genius tribe made their home. Not yet man, but our genetic superiors, these people left on their ceiling paintings of dazzling splendor. Other treasures, artifacts and weapons proclaimed the dizzying speed of their ascent to civilization . . . an ascent wrecked by a shattering quake that drove the few left alive fleeing down the black terror of the subterranean river . . . Styx. Now, once again, the earth has opened. Teams of scientists have entered the ghostly caves of Subrano Man. Until, once again, the earth wrenches and slams shut the only passage to the surface. And, again, a handful of desperate survivors must risk the unspeakable horror of the underworld River of Death . . . Styx.