They moved on warily. Soon they saw spreading below their hill a vast plain of green grain. A heady aroma blew up from the crops on winds that wrote sweeping patterns across the valley.

Irma pointed. “Look—those farmer folk we saw back at the lock.”

With time to observe, they could see the farmers were leathery at some joints but otherwise sported plumage that rippled with colors in intricate designs. Clad in loose-fitting coveralls, they formed teams that worked on snaking tubular watering systems, focusing the misty, arcing plumes over great distances. They worked hard in their fields, using four-footed animals to draw and plow.

“It’s like farming centuries ago,” Terry observed. “Hard work, very little powered machinery.”

“It’s not as though they can drill for oil, is it?” Aybe said.

“Plenty of solar power available,” Terry said. “And this has gotta be the most high-tech place in the universe.”

“Maybe they like manual work,” Howard said. He looked at their skeptical faces and shrugged. “Just because we’ve been living the rugged life for a while and find the idea unappealing doesn’t mean these things do.”

Irma raised skeptical eyebrows. “Could be, I suppose. But—” She zoomed her vision and stared at the field below. “—they’re coming.”

Cliff looked closer. “Not the farmers. Something else.”

Irma added, “Yeah. Fast.”

These were even bigger, with long necks—something like elongated, feathery racehorses that strode on two legs, with long wiry arms held forward for balance as they cantered. Plenty of rich plumage but a muscular look to them, especially in the legs. Clothed only at the middle, they had thick belts with things like tools dangling from them. As Cliff watched, one of them looked around and eerily looked right at him. It was running hard but held its head fixed, the eyes large and glittering. Not farmers, no.

“Looks like they’re about a klick away,” Terry said. “We must’ve hit some trip wire or detector.”

Cliff had wondered how this place could have developed different intelligent species. Specialization for labor or life niches? They probably had genetic technology, so maybe had developed new species from some early root genetics. Humanity had yet to do that.

Enough thinking; it was hard to avoid it, his head full of questions. The runners, he saw, were perceptibly closer.

“Let’s get going,” Cliff said, and did so.

The menacing pursuers were fast and far more than anybody wanted to fight. Terry led the way, running as if devils pursued him—and just maybe, Cliff realized, they did. Humans had invaded this biosphere unannounced. They had not surrendered meekly, but instead fled from the air lock. No negotiation. Now they were ranging around in somebody’s territory, killing local wildlife to eat. The farmers seemed peaceful and simple, but that couldn’t be the whole story here.

But could they outrun those things?

On the run they decided, amid hoarse, barked consultation, not to return along their earlier route. There seemed little shelter there. Instead they headed downhill from the next ridgeline. They had learned a long, loping stride that took advantage of the lower gravity. No sign of pursuit yet in the forest behind them. They stopped to listen—panting pretty loudly, then holding their breaths to hear.

A distant chippering cry. Beneath that, low growling. Coming closer. “And they know the territory,” Cliff whispered.

They ran. Nobody suggested negotiations.

They hurried into a broad, low valley of gnarled trees. Some bore fruit, and Cliff felt a pang of hunger as they ran through these. It was moist here and soon they heard the snarl of water over rapids. The river was broad and Cliff wondered whether they could ford it. He glanced left and right and saw a long arched bridge. “That way!” They all veered toward the bridge, puffing heavily now.

Terry, who had started off fast, now brought up the rear. Not a distance guy, Cliff thought, and knew that he wasn’t going to last much longer, either. He tried to think of something to do. Anything.

He studied the bridge as they slogged toward it. He could hear the high, skating cry clearly now. Closer.

The bridge was made of stone cemented together, very old style construction. On the underside, though, were thick metal beams, ribbed and with flanges at each side. Rugged.

They reached the foot of the bridge. Maybe the lighter gravity gave them some edge here, but it was all gone. He slowed, thinking frantically. Stopped. An idea flashed.

“Hey. Let—let’s hide.”

Aybe gave him a sharp you’re crazy look. Irma was so winded, she just bent over and gasped.

“We’ll get run down,” Cliff said. “I wouldn’t count on our lasers taking these things out, either—they’re big and look pretty damn tough to me. And … they’re clothed. Belts, tools. Maybe they’re armed, too.”

He let this sink in while he puffed, and now they could hear the cries behind them quite well. They all looked at one another, gasping, coughing, and finally Irma said, “I can’t go much more. Let’s try it.”

The men nodded, looking relieved. Good psychology, Cliff thought—they still felt that they had to protect the woman. He trotted around to the underside of the bridge and grabbed one of the ribs. He hadn’t really thought this through, but when he put his boots on the side flanges, he found they fit, barely. The others watched as he climbed up the ribs. He then turned carefully to face down toward the water that swirled and chattered over rocks. With some effort, he could strain back and support himself against the beam.

The others looked up at him doubtfully. Aybe said, “Hanging with both hands? We can’t use the lasers from there.”

Cliff called down, “What else can we do?”

That decided them. They inserted themselves into the nooks between the beam flanges and with some grunting got pinned into place. It was an effort and he could feel his arm muscles working hard.

“Hold on as long as we can,” Cliff said. The chippering was close. “Quiet.”

Pounding of heavy feet. Growls from deep guts, wild shrieks, quick barks like commands. Thumps. Feet hammered at his back, or that’s how it felt, and most of them passed on. But then he heard a huffing from above, heavy long breaths. Feet padded around, slapping on stone. A rumbling bass grunt that seemed to go on forever. His stinging arm muscles had locked solid, his fingers trembling. The thing above wouldn’t leave. Maybe the pursuers had left one here to block their retreat?

He didn’t like this conclusion, but as moments crawled on he saw that it wouldn’t matter. Irma’s face was white with strain and Cliff wasn’t going to last much longer, either. At least they had caught their breath.

He didn’t dare whisper. Catching the eyes of the others, arrayed in the beam slots, he nodded down at the riverbank. They frowned, then got it. Cliff listened intently and caught footfalls above, a scraping that moved to the left of the bridge.

The stream splash might mask any noise they made. He nodded vigorously to them all and jumped down, landing as softly as he could. They followed as he moved to the right. Irma landed off balance, but Aybe caught her before she fell into the stream. Lasers at the ready, they ventured out from the bridge’s shadow.

The shape above came back toward the high stone railing. It towered above, a long snaky head looking across the river—and Irma hit it clean and sure with a long bolt. The head jerked, looked down at them with those big, glittering eyes—and toppled backwards. They raced around, got on the bridge—and stopped to gaze at the big thing.

A deep burn at the top of its skull trickled pale blood onto the stones. The eyes blinked, but the eyeballs did not move. Cliff unbuckled the belt from the thick waist and put it around his own. The tools were odd and heavy. He was tempted to take a look at them, but—