Doc Savage: Death's Dark Domain First edition

A dying man is discovered, blinded and drained of blood, clutching a defaced bat medallion in the forbidden region known as Ultra-Stygia. With his last words, he warns that the gates of Hell have burst open--and no one is safe. This is only the beginning of a horrific chain of events that summons Doc Savage to a vampire-haunted zone between two rival powers vying for control of the least habitable spot on Earth. Why? What was the dark secret of Ultra-Stygia--over which warring nations spill rivers of blood? Only the mighty Man of Bronze dared its bat-infested caverns in search of the unexpected answer!