And from the village jailhouse, opposite the row of fire-wracked ruins, hollow, booming laughter mocked him. There a Callistan combat pilot, captured some time ago when his ship had been shot down, clutched the bars of his prison's window with slender, furry, three-fingered hands, and made derisive, gloating remarks in his sketchy English. "Eart'men! Vaah!" he taunted, his words rumbling in his vast chest. "Very little while--all done--you--here--Titan! Titan be--Mado-Achar--New Achar--New Callisto! Very little while we build shiny metal house here! You find out! You know already! Eart'men! Vaah! Huah!" And then he would laugh, the breath sizzling in his wide nostrils, his little, close-set eyes, that peeped, like a poodle-dog's through the thick fur that covered his face, reflecting the flames and seeming to glow in appreciation of the situation, and of the choice Acharian insults he had hurled. As he helped fight down the fire, Ron Leiccsen glanced often toward the defiant captive, wondering intently about all his kind. Tough and hardy, and immune to all terrestrial germ diseases, the Callistans came from a strange world of spore-plants and burnished, bizarre cities, over which a steady, cool climate brooded. Achar--Callisto--being a satellite of Jupiter, was far from the sun, too. But because Achar had a radioactive core, generating heat constantly, its surface was far warmer than would otherwise have been possible. And so there was life, there. It was a different kind of life, in many minor respects, than that of Earth. In that thin, cool atmosphere, nature had omitted certain biological phenomena. Others of the fire-fighters hurled insults back at the captive Callistan--furious, defiant curses which showed that no sane argument could ever win a good half of them to retreat. * * * * * Anna Charles was climbing into the cabin of her sleek, black space flier, which rested on the landing platform on the flat roof of the house where she lived. She was prepared to seal the door, when a booted foot was thrust against it, preventing her action. A slow, admiring grin was turned upon her. The sullen, half-humorous line in the intruder's bronzed cheek, was like a steel wall, against which her fury and her surprise and contempt lashed in vain. "Ron Leiccsen!" she choked. "I was ready to start for Mars! What do _you_ want? You and your negative talk!"