Chapter 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.

"The trailer herd," said Torcred. "Thousands on thousands of them, moving south with the sun that feeds them. The fall migration is farther west this year, and they are coming in greater numbers than any of our troop can remember."

The girl said nothing. He added irritably, "You understand--there will be good hunting."

She shocked him by laughing. "Is that all you think of?" she inquired mockingly. "Good hunting--a full stomach and a full fuel tank. You crawlers lead poor, empty lives."

"We don't crawl," said Torcred shortly, eyes fixed on the speedometer that registered a hundred miles an hour.

The bird-girl laughed again. "You know so little, you earthbound creatures," she taunted. "You've never known the joy of flight--to climb up and into the clear bright stratosphere, and see the Earth with all its secrets unroll below you.... _You_ creep from place to place and cower in your camps, but we range farther than you dream, and know the world and all its peoples that fly and swim and crawl and burrow. And we are the highest race of all."

"Higher than the buzzards?" asked Torcred.

She hesitated, then said defiantly, "Of course! Those evil things are huge and powerful, but we'll defeat them in the end, never doubt it. And then--we will have the rule of the sky, which is the rule of the Earth."

She sounded very certain, and Torcred could think of no adequate counter-argument. He said brutally, "We? Who do you mean? _Your_ wings are clipped, bird!"

Then unexpected remorse stung him as he saw how the girl shrank into herself, how the brief glow of enthusiasm left her face. She made no answer, and Torcred too fell sullenly silent.

* * * * *

In silence he closed the throttle and the hurtling terrapin slowed. Close ahead, now, the trailer herd was an amorphous black river in the gathering dusk. Earth and air shook to its thunder, the rumbling of countless wheels and engines and couplings and the strident bleating of thousands of horns as the vast herd jostled and protested.

Closer and closer to the flank of the moving mass rolled the little terrapin, darting over the crests of the dunes and stealing along under their cover. The girl's eyes grew wide at the glimpses they had of that dark dangerous-looking stream; she seemed to flinch from its pounding clamor.

Torcred smiled grimly as he brought the terrapin to a poised halt half-sheltered by a low swell. A scant hundred yards away the migrating trailers rolled obliviously past, one close behind the other, huge box-like monsters on wheels behind a tiny cab. Torcred knew their ways of old; the trailer sections housed women and children, who tended the apparatus that made food, fuel, and ammunition from sunlight and water and air and the minerals extracted from the sterile soil. The trailer-men were drivers and gunners; but the great machines were clumsy and ill-armed, finding safety against the fierce mechanical predators chiefly in their numbers.

The Terrapin waited only for moments; then he opened his throttle wide and sent the little combat car swerving into the heart of the herd.

All around rolled rumbling iron giants; the clank of couplings, the roaring of unmuffled engines were deafening. A hooting of furious horns arose as the terrapin darted and zigzagged between the moving units of the herd. But there was no blaze of gunfire.

"So we hunt them," Torcred flung over his shoulder at the breathless girl. "They can't shoot when we're in among them; we disable one and shelter behind it until the herd passes on...."

The terrapin dashed through narrowing gaps, slowed and spurted again, as Torcred threaded his way skilfully on an oblique course across the roaring stream. At last he saw open ground ahead; he grinned exultantly and put on a final burst of speed that carried him into the clear. The little car swooped with a sickening rush into a shallow valley, and behind it thundering flashes leaped along the flank of the trailer herd and bullets exploded around or ricocheted screaming overhead.

As he slowed to a more moderate pace under cover of the farther dunes, Torcred turned, still grinning, to the bird-girl. "That," he commented, "was the dangerous part."

She shivered slightly. "I was afraid," she admitted candidly.

"That's hardly as simple as attacking a mere crawling terrapin from the air, eh?"

The girl turned her face away. "That was necessary, terrapin ... I passed my fledgling examination only two days ago; it was my second flight beyond the safety zone. The novice must defeat some machine of prey in single combat, before he is accepted."

"And if he fails?" Torcred's eyes were fixed ahead, where a pale light was reflected by the ground that was flat now and gleamed whitely, encrusted with salt.

"And if he--or she--fails," the girl's voice dropped low, "it is the last time." A sob came into her voice. "Even if I could go back to my people, I would be degraded to menial labor or breeding--could never fly again."

Torcred felt pity for her despite his prejudices; and at the same time her words recalled his own worries, and he frowned blackly. The girl mistook his expression for an indication that she had somehow said too much, and she sank back into brooding silence.

She glanced up only when the car's wheels ground to a stop on the salty crust, and Torcred, with a relaxing sigh, was already unsnapping his safety belt and switching off the panting motor. The girl saw flames and shadows amid which black figures moved, and she shrank back in fright, uncomprehending. As the Terrapin flung open his door, mingled sound of clanging metal and hissing fire rushed in to increase her confusion.

He paused momentarily; his expression was unreadable as he gazed on her white face.

"Stay where you are and make no noise," his low voice rasped sternly. "I'll come back."

Torcred closed the door firmly and heard its lock click. The girl, if she foolishly wanted to escape, probably could not find the catch inside, and there was nothing she could hurt herself with if she still felt suicidal. There at least she would be safe from prying eyes, until he could untangle the tumult of unaccustomed emotions that were struggling within him. A terrapin had only one place to himself, the interior of the fighting machine--those with families, of course, knew no such word as privacy.

He turned, straightening his back resolutely, and advanced into the midst of the terrapin camp.