“Surrender!” the Arab woman insisted from the hall. “All surrender!”

“I don’t think that will work anymore,” Nadia said, and ran for the building’s lock.

A part of her was immensely relieved to be able to do something, to stop huddling in a building watching disasters on TV, and do something. And Nadia had platted and overseen the construction of Lasswitz, only six years before, so now she had an idea what to do. The town was a Nicosia-class tent, with the farm and physical plant in separate structures, and the water station well off to the north. All the structures were down on the floor of a big east-west rift called Arena Canyon, the walls of which were nearly vertical and half a kilometer high. The water station was located only a couple hundred meters from the canyon’s north wall, which in that area had an impressive overhang at the top. As Nadia drove with Sasha and Yeli to the water station, she quickly outlined her plan: “I think we can bring down the cliff onto the station, and if we can, the landslide ought to be enough to cap the leak.”

“Won’t the flood just carry the landslide’s rock away?” Sasha asked.

“It will if it’s a full aquifer outbreak, sure. But if we cover it when it’s still just an uncapped well, then the escaping water will freeze in the landslide, and hopefully form a dam heavy enough to hold it. Hydrostatic pressure in this aquifer is only a bit greater than the lithostatic pressure of the rock over it, so the artesian flow isn’t all that high. If it were we’d be dead already.”

She braked the rover. Out the windshield they could see the remains of the water station, under a cloud of thin frost steam. A rover came bouncing full speed toward them, and Nadia flashed their headlights and turned the radio to the common band. It was the water station crew, a couple named Angela and Sam, rabid with the adventures of the last hour. When they had driven alongside and finished their story, Nadia explained to them what she had in mind. “It could work,” Angela said. “Certainly nothing else will stop it now, it’s really pumping.”

“We’ll have to hurry,” Sam said. “It’s eating the rock at an unbelievable rate.”

“If we don’t cap it,” Angela said with a certain morbid enthusiasm, “it’ll look like when the Atlantic first broke through the Straits of Gibraltar and flooded the Mediterranean basin. That was a waterfall that lasted ten thousand years.”

“I never heard of that one,” Nadia said. “Come on with us to the cliff and help us get the robots going.”

During the ride over she had directed all the town’s construction robots from their hangar to the foot of the north wall, next to the water station; when the two rovers got there, they found a few of the faster robots had already arrived, and the rest were grinding over the canyon floor toward them. There was a small talus slope at the foot of the cliff, which towered over them like an enormous frozen wave, gleaming in the noon light. Nadia linked into the earthmovers and bulldozers and gave them instructions to clear paths through the talus; when that was done, tunnelers would bore straight into the cliff. “See,” Nadia said, pointing at an areological map of the canyon that she had called onto the rover’s screen, “there’s a big fault there behind that whole overhanging piece. It’s causing the lip of the wall to slump a bit, see that slightly lower shelf at the top? If we set off all the explosives we’ve got at the bottom of that fault, it’s sure to bring down the overhang, don’t you think?”

“I don’t know,” Yeli said. “It’s worth a try.”

The slower robots arrived, bringing an array of explosives left over from the excavation of the town’s foundation. Nadia went to work programming the vehicles to tunnel into the bottom of the cliff, and for most of an hour she was lost to the world. When she was finished she said, “Let’s get back to town and get everyone evacuated. I can’t be sure how much of the cliff might come down, and we don’t want to bury everyone. We’ve got four hours.”

“Jesus, Nadia!”

“Four hours.” She typed in the last command and started up their rover. Angela and Sam followed with a cheer.

“You don’t seem very sorry to leave,” Yeli said to them.

“Hell, it was boring!” Angela said.

“I don’t think that’s going to be much of a problem anymore.”

“Good.”

The evacuation was difficult; a lot of the town’s occupants didn’t want to leave, and there was barely room for them in the rovers at hand. Finally they were all stuffed into one vehicle or another, and off on the transponder road to Burroughs. Lasswitz was empty. Nadia spent an hour trying to contact Phyllis by satellite phone, but the comm channels were disrupted by what sounded like a number of different jamming efforts. Nadia left a message on the satellite itself: “We’re non-combatants in Syrtis Major, trying to stop the Lasswitz aquifer from flooding Burroughs. So leave us alone!” A surrender of sorts.

Nadia and Sasha and Yeli were joined in their rover by Angela and Sam, and they drove up the steep switchbacks of the cliff road, onto the south rim of Arena Canyon. Across from them was the imposing north wall; below to the left lay the town, looking almost normal; but to the right it was clear something was wrong: the water station was broken in the middle by a thick white geyser, which plumed like a broken fire hydrant, and then fell into a jumble of dirty red-white ice blocks. This weird mass shifted even as they watched, briefly exposing black flowing water which frost-steamed madly, white mists pouring out of the black cracks and then whipping downcanyon on the wind. The rock and fines of the martian surface were so dehydrated that when water splashed onto them they seemed to explode in violent chemical reactions, so when the water ran over dry ground, great clouds of dust fired off into the air and joined the frost steam swirling off the water.

“Sax will be pleased,” Nadia said grimly.

At the appointed hour, four plumes of smoke shot out of the base of the northern wall. For several seconds nothing else happened, and the observers groaned. Then the cliff face jerked, and the rock of the overhang slipped down, slowly and majestically. Thick clouds of smoke shot up from the bottom of the cliff, and then sheets of ejecta shot out, like water from under a calving iceberg. A low roar shook their rover, and Nadia cautiously backed it away from the south rim. Just before a massive cloud of dust cut off their view, they saw the water station covered by the swift tumbling edge of the landslide.

Angela and Sam had been cheering. “How will we tell if it’s worked?” Sasha asked.

“Wait till we can see it again,” Nadia said. “Hopefully the flood downstream will have gone white. No more open water, no more movement.”

Sasha nodded. They sat looking down into the ancient canyon, waiting. Nadia’s mind was mostly blank; the thoughts that did occur to her were bleak. She needed more action like the last few hours’, the kind of intense activity that gave her no time to think; even a moment’s pause and the whole miserable situation crashed back in on her, the wrecked cities, the dead everywhere, Arkady’s disappearance. And no one in control, apparently. No plan to any of it. Police troops were wrecking towns to stop the rebellion, and rebels were wrecking towns to keep the rebellion alive. It would end with everything destroyed, her whole life’s work blown up before her eyes; and for no reason! No reason at all.

She couldn’t afford to think. Down there a landslide had overrun a water station, hopefully, and the water rushing up the well had been blocked and frozen, making a composite dam. After that it was hard to say. If the hydrostatic pressure in the aquifer was high enough, a new breakout might be forced. But if the dam were thick enough… well, nothing to be done about it. Although if they could create some kind of escape valve, to take the pressure off the landslide dam…