Note: According to Stefan Dziemianowicz in the introduction to the Hippocampus Press edition: The Hippocampus Press edition follows the text of the original serial publication. The serial version in "Science and Invention" is at least 20% shorter. The version for the "Famous Fantastic Mysteries" appearance was revised by Merritt and is about 10% shorter than the serial version. This is Merritt's preferred text. Most subsequent book publications are based upon this version.

Synopsis: From the back cover of Avon book 315: Was she witch-woman or just the metal emperor's slave-girl? Hidden in the heart of unknown Asia, a fantastic world of living metal waited. Monsters of solid metal, pulsating with an unearthly electric life, wise with wisdom not of this world, and dreaming of the day when its harder-than-steel horde, mountains high, could roll forth smashing and killing and flattening the world of mere humans. Holding back this monster army was the figure of a woman - Norhala. Seemingly human, beautiful beyond comparison, with all the fickleness and tenderness of a young virgin, yet possessed of powers beyond science's conception. Norhala was the key to these horrors - and the four Americans who blundered into her domain unintentionally started a chain of events that would bring to a climax this danger to the world.