The Iron Breed by Andre Norton

their bodies were straps from which hung cords. The People here were prisoners; some—some were pictured in cages!
    Jony snarled. Just as he thought, those who had lived here had the same evil nature as the Big Ones even though they looked like himself! The People in their time had escaped, just as Rutee and he had gained freedom. Evil—he felt now he could sniff the evil in this as if as rank and air-filling as the stench of the Red Heads!
    “What were they doing?” Maba asked still intent on the picture. “Why do the People have those things on them?”
    “Because,” Jony said between his teeth, “they were prisoners—prisoners of evil ones. As we were once. Oh, let us get out of here!”
    He pulled her on. There must be some way out; he had to find it!

SIX
    They finally reached the end of that huge space. Jony was unable to judge just how large it was because of all that was crowded into it. Here stood another gleaming door, twin to the one he had forced open at the other end. To his surprise, just as he was wondering how effective his mistreated staff might prove for another such assault, Maba moved confidently forward. Standing on tiptoe, she put her two hands as far up as she could reach so that they met in a slight depression.
    “Maba!” Jony was reaching to snatch her back when he saw that the door line was enlarging, reluctantly. They could catch a faint grating sound from within the wall, the first sound save those they themselves had made to be heard here at all.
    The crack was wide enough open now for Maba and Geogee. But Jony did not trust it in the least. He turned about, grabbed at the stacked colored boxes, catching one which yielded to his tugging. With this he wedged the door panel, holding it open.
    They passed into another gray-lit, plain-walled passage. However, this slanted upward, and Jony hoped that that meant they would eventually reach the surface and freedom. He had no idea of what this place was, save that the ones who had built the walls with their rods had apparently gathered therein things which they had made and perhaps treasured.
    There was a crackling from behind; Jony whirled, shaft ready. All he saw was that the brace he had put in the doorway was being crushed by the weight of the closing panel, though the debris kept it from closing completely.
    Maba—how had Maba learned the secret of the doors? He was more than a little puzzled by that. Now he asked her directly.
    “I could see there was a line,” she answered promptly. “And I kept feeling along up and down. 'Cause that's the way the wall opened before—when I put my hands on it.” She smiled with that particular smile she used at times when she believed that she had been clever. Maba was only too ready to believe in her own powers, and lacked the wariness which Jony had learned in the cages when he was far younger than she was.
    “Jony,” Geogee had been scuffling along, frowning a little, as if some thought was troubling. “Those People on the wall—you said they were prisoners—like you and Rutee. But the others, the new ones, they looked like us, not as you said the Big Ones do. If they were like us—why would they shut up the People, make them wear those straps around their necks, stay in cages?”
    “You heard what I said to Maba,” Jony gave the best answer he could summon. “Just because those in the pictures look like us, that doesn't mean they were like us inside. We know the Big Ones are bad, and they look different, so we learned from the beginning to be afraid of them. But the mind-controlled—they were like us. Yet they did just what the Big Ones told them. So unless we were sure, we could not trust them, ever.”
    “Then those in the pictures were mind-controlled?” Geogee demanded.
    “I don't know.” Jony could not somehow believe that the very alien Big Ones were responsible for the building of this place. The sky ship picture had alarmed him at first glance. But then, Rutee had told him