"He knew about you. Oh, he was brilliant, Tyr--or Ted! He knew your function. He called you a mutant, darling. No stomach, no lungs, no need for water. The future man! I can see, now that my eyes have been opened. It is Nature, striving all the time for perfection, equipping her products with the necessities to get along in their environments! In you she is fitting man for space travel, darling! "Out there among the stars, without lungs and with no need for food or water, you could strip a ship down and really travel. Light-years wouldn't mean a thing to you. Just a battery of sun-lamps to feed you. You wouldn't age hardly at all, for you derive your heat from outside sources, instead of generating it in your tissues, as normal men do! Your organs merely transmit the heat and energy into your muscles and brain. There is no food to be digested and churned into energy, to be broken into heat-energy in the cells. Your energy comes from outside!" "You make it sound important." "It _is_ important! I feel I don't understand _how_ important you really are." Grimly he said, "Now if only we could convince the _ardth_ and the Trylla of that!" Katha caught his arm, saying fiercely, "Tyr--Ted--oh, I'll call you Tyr! You can't give up. You must fight. The _ardth_ are fighters, Tyr. Your father was a fighter. He came here with his wife because he had space leprosy! That's right. And his wife came with him. You were born on Lyallar--far, so far from your home planet. He died a long time ago, did William Rohrig, but his fighter's heart didn't die." A red fingernail stabbed into the flesh of his chest. "That heart is in you, Tyr. It wants to fight. Maybe it doesn't know how, but you are sad only for that reason. You aren't fighting!" Tyr whispered hoarsely, "Tell me how, Katha. How shall I fight?" "How do you want to fight? What does your heart and your brain tell you?" He stood and let the sunlight hit his forehead. It grew hotter and hotter as he stood there, and inside his skull he felt something stirring, and knew it for his opening brain. _Fight them where they are most vulnerable, Tyr. Hit them at their core!_ The inner voice that was his thought whispered again, _Destroy the Glow!_ "I must destroy the Glow," he said to her. Katha shuddered, whispered in horror, "You cannot! You would die from it long before you ever came to it. The Glow is terrible, awesome, Tyr!" The sunlight made a pattern on his chest as he turned. "Nevertheless, that is what I must do." The woman bowed her head and took his hand. * * * * * The city of Mart sprawled like a lazing slug upon the prairie. Aircraft sped across its walls, winging into illimitable distances. The deep hum of tradesmen's voices as they called their wares mingled with the smooth roll of gyrocars, rising to form the soul of the great metropolis. Armed guards clanged along the tops of the pyramidal walls.