Chance was with them this time. The first sandcar they found still had the keys in the lock. It was battery powered, but contained a full charge. Much quieter than the heavy atomic cars it sped smoothly out of the city and across the sand. Ahead of them the sun sank in a red wave of color and it was six o'clock. By the time they reached the tower it was seven and Brion's nerves felt as if they were writhing under his skin. Even though it looked like suicide, attacking the tower brought blessed relief. It was movement and action, and for moments at a time he forgot the bombs hanging over his head. The attack was nerve-wrackingly anticlimactic. They used the main entrance, Ulv ranging soundlessly ahead. There was no one in sight. Once inside they crept down towards the lower rooms where the radiation had been detected. Only gradually did they realize that the magter tower was completely empty. "Everyone gone," Ulv grunted, sniffing the air in every room that they passed. "Many magter were here earlier, they are gone now." "Do they often desert their towers?" Brion asked. "Never. I have never heard of it happening before. I can think of no reason why they should do a thing like this." "Well I can," Brion told him. "They would leave their home if they took something with them of greater value. The bombs. If the bombs were hidden here, they might move them after the attack." Sudden fear hit him. "Or they might move them because it is time to take them--to the launcher! Let's get out of here, the quickest way we can." "I smell air from outside," Ulv said, "coming from down there. This cannot be, because the magter have no entrances this low in their towers." "We blasted one in earlier--that could be it. Can you find it?" Moonlight shone ahead as they turned an angle of the corridor, and stars were visible through the gaping opening in the wall. "It looks bigger than it was," Brion said, "as if the magter enlarged it." He looked through and saw the tracks on the sand outside. "As if they enlarged it to bring something bulky up from below--and carried it away in whatever made those tracks!" * * * * * Using the opening themselves they ran back to the sandcar. Brion ground it fiercely around and turned the headlights on the tracks. There were the marks of a sandcar's treads, half obscured by thin, unmarked wheel tracks. He turned off the lights and forced himself to move slowly and to do an accurate job. A quick glimpse of his watch showed him there were four hours left to go. The moonlight was bright enough to illuminate the tracks. Driving with one hand he turned on the radio transmitter, already set for Krafft's wave length.