“Quiet!”

Look, the EM is moving off and Bob’s got an idea that I can check your systems out before we try to move you or—

“Come on if you bloody well must, but keep quiet.”

The EM is gone, swallowed in the sullen red gloom. Nigel peers about him and sees more of the ruts cut into rock, lets his eyes be led by the sloping lines down the canyon. From this angle the design is at once apparent. Troughs intersect in a downward-tending web, emptying here and there into small holes near the canyon walls: cisterns. Farther on, a gust clears the air for a moment and Nigel sees a spillway, the brown rock that forms it worn and eroded but still functional, and beyond, a crude catch basin. So the EMs gathered water here, stored it. But there is no agriculture.

I’ve got you in the IR, Nigel. Just hold still, don’t try to move.

“I told you, mind the transmissions.”

No trouble, I’m sure that—

It comes at them with amazing speed, knees jerking high. It scrambles over boulders. Daffler emerges from the veils of dust and does not see the EM bearing in from the east. Daffler is a hydrasteel walker, like Nigel, and he looks forward through forward-focused, mag-adjusted opticals so he is blind to the east unless he turns his sensor head; but as he lumbers forward, now only meters away from Nigel, the dust falling thick and white-streaked again, the EM lunges and strikes Daffler from behind. “Roll!” Nigel calls, the word leaping out of him in his amazement, but Daffler cannot draw his forward legs up in time and the walker pitches over, scraping on the rocks, orange sparks scratching the air, and the EM steps over the tumbling robot that now seems so weak. Nigel backs away from the towering dark figure, watches its head dip and turn away from Daffler and toward Nigel, the thing is sure of where he is, must have gotten a fix on him earlier and not given any sign, simply waited them out, Daffler shouting now got to ’bort out, something hit me as the huge head sways, Nigel feels Daffler tumble against him, jarring, legs a tangle, and senses a sudden spattering of radio pulses, a highly structured wave form, and then a loud crisp sound like fat frying as the EM lifts Daffler and brings him down on Nigel’s deck, crunching, a lancing pain, bright burst of green—

The medmon moved with rectangular urgency; sniffing at him, humming to itself. Nigel lay passively, wanting this to be over. He eyed the ceiling.

“That thing for sure took you and Daffler to the cleaners,” Bob Millard said casually.

“It came at us like a bat out of hell. Otherwise, I’m sure—”

“We’re sure of nothin’, Nigel.”

“Well, I am sure I don’t need this thing”—he thumped the medmon appendage—“nosing about me. Christ, Bob, I was tucked away in the servo capsule, not down on Isis. I can’t possibly be hurt.”

Bob shrugged. “This is SOP, according to Medical. Any big accident, we put you through.”

“Then why isn’t Daffler here?”

“His unit wasn’t creamed, ’at’s why. We’re still getting a carrier and inboard diagnostics from his walker. Yours—zip.”

“The EM must’ve smashed into my outer circuitry. That could precipitate a shutdown in the whole—”

“Could be. Thing is, we can’t go back and see right away. Have to wait.”

“Why?”

“A whole flock of EMs have moved into that ‘village’ of yours. Ted ’n’ I feel we shouldn’t risk further contact with ’em right now. They’ll be waitin’.”

“I want to look at those superconductors.”

“So does half the crew.”

“Then perhaps—”

“No go, Nigel.” Bob smiled lazily. “The EMs’ll defend that town or whatever it is. Y’know, in all this, you kinda forgot what I sent you down there for.”

Nigel saw he was going to have to go through this mild byplay to find out what the tac-strat people thought was the next smart move. “What was?”

“Figure out what’s makin’ ’em so jumpy.”

The spot on Isis lying directly under Ra’s glow is bleak and fevered, its dull heat a remorseless engine.

Air drives out of the Eye, cloaking the land with dust, and shadows blur the forms moving on the slopes of the hills. The mountains above mutter like an old man swearing in his sleep.

A shock wave ripples through the carapace of the robot, another shifting of the earth as the churn of the planet cycles and recycles the crust endlessly, quakes and slides and upwellings bringing fresh iron forth to lick the winds and bind up the oxygen. And volcanoes belch forth more water, which in turn is split by random energetic photons into hydrogen and oxygen, elements feeding the ecology that clings to the planetary crust, frail life, suffering the jolts and the million minor deaths and the dry bareness. Gales pour over the mountains with their dust, carrying a howl that never ends in these narrow valleys, hollow and vacant and without hope of change, reedy and distant, as though the air itself is worn out.

He moves on, clump, crump, leaden steps carrying him across the silted valley floor toward the hills, ceramic sheaths of his hydraulic rasping, a bitter taste of a stim tab is his mouth. Onward.

Daffler is in the lead and a woman, Biggs, is approaching the clustered EMs from the other flank of the volcano. Orange flash: the mountain mumbles, and the land is for a moment awash in fresh light. The dust thins as the moist volcano breath washes away the sulfur oxide blur from the Eye. Alex has never seen a group of EMs bunched together like this on the radio maps. Something brings them here, away from the “village,” so a team now approaches the EMs while a larger team invades the “village” again, to take a look at a superconductor sheet, crawl into the caves, learn what they can. Daffler and Nigel and Biggs are a diversion, an afterthought really, to watch the EMs but do nothing else. If contact is to be made it must come from the specialists, the encoders and analysts who have sat silent and waited, stern and close-lipped, for more input. The biomeds have trapped a myriad of small animals by now, picked them apart, and found nothing that echoes the semiconductor nerves and brain of the EMs. The animal kingdom of Isis is slow, ordinary, run by the grinding inefficient chemical processes of oxidation in an atmosphere where iron and sulfur steal the oxygen at every turn, leaving life to snatch what it can before the oxygen-rich volcanic air is locked up again, for a billion years, in the hungry rocks. Yet it is not oxygen the EMs seek near this volcano; Nigel sees this, watching their shifting specks on his overlay. They do not congregate where the drizzle descends, bringing oxygen.

Sighted one to the south. Headed toward me. I’m not moving.

“Right.” Daffler sounds tight, cautious. As he bloody well might be.

Suggest you bear on it, following an axis through me. That way it’ll see no lateral motion.

“Right”

Nigel plunges on, legs working. Something skitters by him. A small rodentlike thing, running as fast as it can. The animals here have anaerobic reserves, just as Earth-side animals, but they are weak and last only a few minutes. After that, they must slow to the rate dictated by the oxygen supply. Nigel peers ahead. Clouds are sweeping in, drawn by the convection call near the volcano, and the ruddy cranberry glow soaking down reminds Nigel of the aura over a distant burning city, the way cities had been devoured since ancient Egypt, the libraries in flames, Alexandria—

It’s passed me.

Another small creature, running to the left.

Bob’s voice came through clearly:

Guess you oughta hunker down, Nigel. Don’ want a repeat a last time.

Nigel obligingly stops all servos, settles to the ground, tapers off his carrier waves in X- and K- and R-band. A howling of wind. An orange flash from the crater high above. Something moving: dog-sized, four legs, matted brown coat, tongue lolling. Behind it, seventy meters away and closing: an EM, striding smoothly on the baked sands, negotiating a narrow wash, coming on as stolidly as a train. But the EM is tired, too, Nigel sees. The legs waver and the arms are slumped at its sides. This is a pursuit, and a long one, and in the space of time the EM takes to make one stride Nigel pieces together this latest fact, and all the other data on EMs, and sees that of course they are following a carnivore pattern, moving steadily over the land but keeping separated so that each EM has an area to hunt, and between the passing of each EM there is time for the prey to forget, to grow careless. No other creature on Isis has the semiconductor wiring because they have been hunted down, just as man has no similar land competitor because in the far past he eliminated them. The EM slows now, head lifted, peering to the north where the doglike thing vanished, and suddenly it stands erect, stopping, head high and turning east, it seems to gather itself, and Nigel hears again the fast pop-ping sound, crisp, bacon frying, louder, louder, louder, until his receiver circuits overload, and silence washes in.