An alien race, the Skatha, launch space missions to find new sources of beryllium needed to sustain life on their planet. In one probe, Drost and Eila land their craft on earth in the Andes Mountains, and in the search for beryllium ore they ally with the Quechua Indians to extend the Inca Empire. The search for sufficient beryllium stretches into present time, and meanwhile Drost discovers a shocking way of preying on the Indians to sate his appetite for sensory pleasure. The Skatha had lost their bodily, tactile senses when sudden radioactivity on their planet made it necessary to graft a beryllium sheath onto their humanoid forms to survive.Drost learns of a discovery of the rare beryllium ore by an American mining engineer, Josiah, and plots to take possession. However, his mania for power and pleasure, and his discovery of new, mind-bending properties for beryllium, have lead him to alter his mission to the conquest of an earthly empire rather than return to his own planet. Eila joins forces with Josiah to resist Drost's new, malevolent scheme. The conflict takes place worldwide as a shocking denouement closes in.