Outside the valley entrance they hid their boulder cars in a knot of boulders, and Coyote studied weather reports. Maya fumed at the delay, but Coyote shrugged her off. “This isn’t going to be easy,” he told her sternly, “and it isn’t possible at all except in certain circumstances. We need to wait for some reinforcements to arrive, and we need to wait on the weather. This is something Spencer and Sax himself helped me to set up, and it is very clever, but the initial conditions have to be right.”

He returned to his screens, ignoring them all, talking to himself or to the screens, his dark thin face flickering in their light. Alchemist indeed, Michel thought, muttering as if over alembic or crucible, working his transmutations on the planet… a great power. And now focused on the weather. Apparently he had discovered some prevailing patterns in the jet stream, tied to certain anchoring points in the landscape. “It’s a question of the vertical scale,” he said brusquely to Maya, who with all her questions was beginning to sound like Art Randolph. “This planet has a thirty-k span top to bottom. Thirty thousand meters! So there are strong winds.”

“Like the mistral,” Michel offered.

“Yes. Katabatic winds. And one of the strongest of them drops off the Great Escarpment here.”

The prevailing winds in the region, however, were westerlies. When these hit the Echus cliff, towering updrafts resulted, and flyers living in Echus Overlook took advantage of them for sport, flying all day in gliders or birdsuits. But fairly frequently cyclonic systems came by, bringing winds from the east, and when that happened cold air ran over the snow-covered Lunae plateau, scouring snow and becoming denser and colder, until the entire drainage area was funneled out through notches in the great cliffs edge, and the winds then fell like an avalanche.

Coyote had studied these katabatic winds for some time, and his calculations had led him to believe that when conditions were right — sharp temperature contrasts, a developed storm track east to west across the plateau — then very slight interventions in certain places would cause the downdrafts to turn into vertical typhoons, smashing down into Echus Chasma and blasting north and south with immense power. When Spencer had identified for them the nature and purpose of the new settlement in Kasei Vallis, Coyote had immediately decided to try to create the means to effect these interventions.

“Those idiots built their prison in a wind tunnel,” he muttered at one point, in answer to Maya’s inquisition. “So we built a fan. Or rather a switch to turn the fan on. We dug in some silver nitrate dispensers at the top of the cliff. Big monster jet hoses. Then some lasers to burn the air just over the flow zone. That creates an unfavorable pressure gradient, damming up the normal outflow so that it’s stronger when it finally breaks through. And explosives installed all down the cliff face, to push dust into the wind and make it heavier. See, wind heats up as it falls, and that would slow it down some if it weren’t so full of snow and dust. I climbed down that cliff five times to set it all up, you should have seen it. Set some fans as well. Of course the power of the whole apparatus is negligible compared to the total wind force, but sensitive dependence is the whole key to weather, you see, and our computer modeling located the spots to push the initial conditions the way we want. Or so we hope.”

“You haven’t tried it?” Maya asked.

Coyote stared at her. “We tried it in the computer. It works fine. If we get initial conditions of hundred-and-fifty kilometer cyclonic winds over Lunae, you’ll see.”

“They must know about these katabatic winds in Kasei,” Randolph pointed out.

“They do. But what they calculated as once-a-millennium winds, we think we can create any time the initial conditions are there on top.”

“Guerrilla climatology,” Randolph said, eyes bugged out. “What do you call that, climatage? Attack meteorology?”

Coyote pretended to ignore him, although Michel saw a brief grin through the dreadlocks.

But his system would only work with the proper initial conditions. There was nothing to do but sit and wait, and hope they developed.

During these long hours it seemed to Michel that Coyote was trying to project himself through his screen, out into the sky. “Come on,” the wiry little man urged under his breath, nose against glass. “Push, push, push. Come over that hill, you bastard wind. Tuck and turn, spiral tight. Come on!”

He wandered the darkened car when the rest of them were trying to sleep, muttering, “Look, yes, look,” and pointing at features of satellite photos that none of the rest of them could see. He sat brooding over scrolling meteorological data, chewing on bread and cursing, whistling like a wind. Michel lay on his narrow cot, head propped on his hand, watching in fascination as the wild man prowled through the dimness of the car, a small, shadowy, secretive, shamanesque figure. And the bearish lump of their prisoner, one eye agleam, was likewise awake to witness this nocturnal scene, rubbing his scruffy jaw with an audible rasping, glancing at Michel as the whispering continued. “Come on, damn you, come on. Shoooooooooo … Blow like an October hurricane …”

Finally, at sunset on their second day of waiting, Coyote stood and stretched like a cat. “The winds have come.”

During the long wait some Reds had driven from Mareotis to aid in the rescue, and Coyote had worked out a plan of attack with them, based on information Spencer had sent out. They were going to split up, and come on the town from several angles. Michel and Maya were to drive one car onto the cracked terrain of the outer bank, where they could hide at the foot of a small mesa within sight of the outer-bank tents. One of these tents contained a medical clinic where Sax was being taken some of the time, a fairly low-security place according to Spencer, at least compared to the holding compound on the inner bank, where Sax was being kept between sessions in the clinic. His schedule was staggered, and Spencer could not be sure which location he would be in at any given time. So when the wind hit, Michel and Maya were going to enter the outer-bank tent and meet Spencer, who would be there ready to guide them to the clinic. The bigger car, with Coyote, Kasei, Nirgal, and Art Randolph, was going to converge, with some of the Reds from Mareotis, on the inner bank. Other Red cars would be doing their best to make the raid look like a full-scale attack from all directions, particularly the east. “We will make the rescue,” Coyote said, frowning at his screens. “The wind will make the attack.”

So the next morning Maya and Michel sat in their car, waiting for the winds to arrive. They had a view down the slope of the outer bank to the big lemniscate ridge. Through the day they could see into the green bubble worlds under the tents on the outer bank and the ridge — little terrariums, overlooking the red sandy sweep of the valley, connected by clear transit tubes and one or two arching bridge tubes. It looked like Burroughs some forty years before, patches of a city growing to fill a big desert arroyo.

Michel and Maya slept; ate; sat; watched. Maya paced the car. She had been getting more nervous every day, and now she padded about like a caged tigress that has smelled the blood of a meal. Static electricity jumped off her fingertips as she caressed Michel’s neck, making her touch painful. It was impossible to calm her down; Michel stood behind her when she sat in the pilot’s chair, massaging her neck and shoulders as she had his, but it was like trying to knead blocks of wood, and he could feel his arms getting tense from the contact.

Their talk was disconnected and desultory, wandering in random jumps of free association. In the afternoon they found themselves talking for an hour about the days in Underhill — about Sax, and Hiroko, and even Frank and John.