That was absolutely untrue, and was exactly what was bothering the Terrapin. His people kept no slaves and took no prisoners. He barked, beside himself: "You will obey me! Or stay here and die--slowly--of thirst." Her lips parted as if to retort, but her gaze slipped past Torcred to sweep the remote horizon and the dun wilderness that stretched to it without path or landmark. In the two expanses of sand and sky there was no life visible. The thin shoulders under the heavy flying suit seemed to sag. "All right, terrapin," she said with weary disdain. "You win, for the time being." II The little machine held two well enough; married terrapins on the march carried their wives beside them and children stowed somehow and anyhow in the rear compartment. Torcred snapped the catches of his safety belt and motioned the girl to do the same; when she was slow to obey, he leaned over and fastened the belt himself, drawing it painfully tight about her slim waist. Then the engine's hum rose as he opened the throttle; the wheels spun and gripped, and the terrapin bounded away, bearing westward over the dunes. As it picked up speed Torcred was touched by the familiar sense of power and mastery in the deep throb of the motor and the ready surge of the armored car. But he brooded darkly as mountain and desert rolled past in monotonous succession, as the minutes heaped themselves into hours.... The sun was a redhot disc descending into a bath of fire in the west. And minute by minute the angry light crept higher up the sky and assumed new forms, clouds and streamers, for it was a mighty redlit pall of dust that was ever higher and nearer to the rushing terrapin. Torcred glanced sidelong at the girl beside him. Her face was even whiter under the harsh light of sunset, her eyes closed beneath long lashes. Watching that smooth, tragic face, Torcred realized again how young she was; he shook his head somberly. The air-people were a strange race, who sent their young females on missions fit only for grown men. The terrapins were far more sensible. But no terrapin woman had the strange beauty of this alien creature from the sky.... Presently he said, "Look. Ahead." The girl's eyes opened listlessly. They were dark-blue, opaque. But faint interest stirred them as she scanned the view ahead. The flaming dust cloud had climbed to the very zenith; the smell of it was in the terrapin, its feel between the teeth. Miles ahead across the desert, a dim encarmined shimmer marked the waters of the Salt Sea. Nearer, but still far ahead, a black stream was moving across the rippled plain at right angles to the terrapin's course. It was without beginning or end, pouring steadily from north to south. A distant vibration seemed to shake the earth beneath the sway and swoop of the moving vehicle.