Banyon nodded and turned the vehicle around, but as the roar faded behind them

Jonny studied the landscape below with decreasing hope. The Cobras had already established that there weren't any natural obstacles between the herd and the

Menssana, and now that he knew what they were up against it seemed very unlikely they could do anything to the terrain that would make any difference whatsoever.

Something more drastic was likely to be necessary. Drastic and dangerous.

Banyon had apparently reached the same conclusion. "We're going to have to scare them, I'm afraid," he murmured, just loudly enough for Jonny to hear.

"There used to be herds this size all over parts of Earth and Blue Haven," Jonny said. "I wish I knew how they'd been hunted. Well. We don't have anything like real explosives aboard, and we don't yet know what this species' predators even look like. I suppose that leaves close-in work with lasers and sonics."

"Laser range isn't that short-oh. Right. If they don't see us, there's no guarantee they'll figure out which way to run."

"Or even notice they're being killed off." Jonny thought for a minute, but nothing else obvious came to mind. "Well... let's try buzzing them with the car first. Maybe that'll do the trick."

But the animals apparently had no enemies that were airborne. Completely oblivious to the darting craft above them, they continued stolidly on their way.

"We do it the hard way now?" one of the others asked.

Banyon nodded. "Afraid so. But hopefully not too hard. Saving the biologists some work isn't worth anyone getting killed over."

"Or even hurt," Jonny put in. "We'll just-"

A ping from the car's phone interrupted him. "Governor, we've got something here that may or may not mean anything," Captain Shepherd said, his attention somewhere off-camera. "The satellite's been completing its large-scale geosurvey... and it looks very much like that herd is running along one of the planet's magnetic field lines."

Banyon looked at Jonny, eyebrows raised. "I thought the only things that used geomagnetic navigation were birds, insects, and tweenies."

"So did all the Menssana's biologists," Shepherd returned dryly. "But they admit there's no reason something larger couldn't make use of the mechanism."

"If we assume they're indeed paralleling the field lines, is the camp still in danger?" Jonny asked.

"Yes. The probability actually goes up a couple of points."

Jonny looked questioningly at Banyon. "Worth a try," the other grunted.

"Captain, is there anything aboard the ship that can generate a strong magnetic field?"

"Sure-the drive modulators. All we'll need to do is pull off some of the shielding and we'll get enough field leakage to overwhelm their direction finders. If that's what's really happening."

"It's worth trying," Banyon repeated. "How fast can you get that shielding off?"

"It's already being done. Say another hour at the most."

The gently rolling terrain could not by any stretch of the imagination be called hilly; but even so the flatfoot herd was audible long before it could be seen.

Standing a few meters back from the main line of Cobras, Jonny wiped the perspiration off his palms as the thunder steadily grew, hoping this was going to work. In theory, the Cobra's antiarmor lasers should be able to make fungus feed out of the herd if something went wrong... but Jonny couldn't help remembering how hard the equally herbivorous gantuas of Aventine were to kill.

"Get ready," his phone said. He glanced up to see the car as it hovered above and ahead of the Cobras. "You'll see them any minute now. Wait for the captain's signal...."

And the leading edge of the herd came over a low rise, like a dark tsunami clearing a breakwater.

They weren't heading directly toward the Cobras, and in actual size were quite a bit smaller than gantuas, but the sheer numbers and ground-level view more than made up for it. Jonny clenched his jaw firmly, fighting hard against the urge to turn and run for cover... and as the wave poured over the rise a new voice on the phone barked, "Now!"

The answer was a volley of Cobra antiarmor lasers-directed not at the flatfoots, but at the clusters of boulders the Cobras had wrestled into position fifty meters closer to the herd. Very special boulders... and if the Menssana's geologists had been right about that particular formation-

They had. The mix of high- and low-expansion minerals in each boulder could survive for only a second or less under a laser's glare before disintegrating with a crack that was audible even over the herd's rumble. Like a string of firecrackers the boulders blew up as the Cobras continued their sweep... and like firecrackers, they actually produced little more than noise. But it was enough; and as the herd's headlong rush faltered in sudden confusion, Jonny could almost see them lose their internal sense of direction. An instant later the hesitation was gone and the herd had doubled its speed to a flat-out run... but in the slightly altered direction the Menssana's additional magnetic field was defining for them from the ship's new position some ten kilometers away. The flank of the herd would now miss the line of Cobras; and when the Menssana lifted in an hour or so and the flatfoots resumed their original direction their path would be shifted at least a kilometer out of the way of the human encampment.

Theoretically. But there would be time to make sure.

The aircar was dropping toward the ground and the Cobras were beginning to converge on it. "Good job," Banyon's voice came from Jonny's phone. "Let's head back."

The last few clouds had cleared shortly before sunset, and the night sky was alive with stars. Walking hand in hand just inside the perimeter, Jonny and

Chrys took turns naming the recognizable constellations and trying to match the more distorted ones with their Aventinian counterparts. Eventually, they ran out, and for a time they just walked in silence, enjoying the night air. Jonny, his audio enhancers activated, heard the faint roar before Chrys did; and by the time she took notice the steady volume level showed their plan had succeeded.

"The flatfoot herd?" she asked, peering off into the darkness.

"Right," he nodded. "And they're not getting any closer. At least a kilometer away-maybe two."

She shook her head. "Strange. I remember some biology class in school where the instructor took it upon himself to 'prove' that no land animal larger than a condorine could ever evolve with a magnetic sense unless there was some ridiculously high local field present. I wish he was here to see this."

Jonny chuckled. "I remember reading about the old theory that all the native plants and animals on the various Dominion worlds were mutated descendents of spores or bacteria that had ultimately been blown there by solar winds from

Earth. The argument was still going strong when the Trofts and Minthisti were found, I understand, and I have no idea what its proponents made of Aventine. If there are still any of them around. I guess the possibility of making a public fool of yourself is just one of those risks scientists have to face."

"You know, that universal genetic code thing has always bothered me, too," Chrys mused. "Why should all the life we find show the same DNA and protein forms? It doesn't seem reasonable."

"Even if that turns out to be the only workable structure?"

"I've never liked that theory. It seems arrogant, somehow."

Jonny shrugged. "I don't especially care for it either. I've heard the Troft theory is that some major disaster three or four billion years ago nearly sterilized this whole region of space, taking with it an early starfaring people. The algae and bacteria that survived on each world were therefore all from one common stock, though they've since evolved independently."