"They're on our side," I said. "These are, anyway.

"Yeah, reckon so," Tex said. "Much as they're on anybody's side. Except their own."

They were drilling a slant hole from the base of the mountain down under the crater floor. It was a big operation. In addition to the drilling rig, they had to mine ice for water. The drill wouldn't work without a lot of water pumped down the hole.

The drill was fascinating. A big derrick held pipes vertical, and electric motors run by solar cells turned them. Every few minutes the crew would connect another piece of pipe to the one vanishing into the ground. "The drill string's following a kind of soft area in the rock," Tex told us. "We're about two kilometers in already." The pipes turned endlessly, while a stream of dirty water bubbled out of the hole to run off into the sands and vanish a few feet away. Even at this cold temperature it boiled in the thin air of Mars.

We called GHQ at Ice Hill, relaying through the captured ship in orbit above Mars. "It looks pretty good," Erica told Commander Farr. "They've got the hole mostly drilled already."

"How's the cooperation with the university people?" Farr asked.

"It couldn't be better," Erica said. "Dr. Drury's a Project fanatic. And they have this huge effort, drillers, miles of pipe, everything. They're really splendid."

"I'm glad to hear that," Farr said. "Weinbaum isn't getting anywhere in the negotiations. Everything has to be referred to three different committees, and the people who have to make decisions can't be reached - I guess it's just their way. I don't mind telling you I was getting worried, but if your part's going all right, it doesn't matter."

"Doesn't matter?" I took the mike. "Skipper, if they don't get together on this, we can't get home! No fuel for the rocket plane."

"We'll get you home," Farr said. "You just see this thing goes off properly. We're counting on you. When that bomb goes off it'll be the signal for the general uprising in the cities. It will show everyone on Earth that we can make atomic weapons, and it will show the miners and townspeople that we're serious about the Project. It must work, and it must work on time."

"It will," Erica said. "The bomb will work, and I've been over the plan with Dr. Drury. The plug stopping up the volcano is nothing but some hardened granite. The bomb will crack it, and the pressure underneath will do the rest. It will work."

"I'm damned glad you're so sure of it," Farr said. "Because we'll have to surface a lot of our agents just before it goes. If we broadcast an appeal and nothing happens, it will set us back months. Not to mention getting a lot of good people killed. If this thing won't go, let me know before it's too late."

"The odds haven't changed," Erica said. Her voice was cold and distant. "You knew the risks when you decided to do this."

"Yes. There are always risks. This one seems the best chance of ending this war quickly. We'll go with the plan," Farr said. "GHQ out."

"We'll go with the plan," Erica said to me. "And I won't be able to rest until this thing is done. Poor Garrett, I haven't been very nice to be around, have I? I'm sorry, darling."

"It's all right," I said.

"No, it's not. But I can't help it." She came to me and we stood, embracing. "I'm glad you're here, even if you weren't needed," she said.

"That's a hell of a way to put it-"

"Oh, Garrett, I didn't want it that way. But you weren't needed, were you? We're perfectly safe here. The university people couldn't treat us any better."

"Yeah -"

"You sound suspicious," Erica said. "Why?"

"No good reason," I told her. "It's just that this is such a damned big operation. Drillers, miles of pipe, the rig, an acre of solar cells spread out on the mountain side, tractors, permanent buildings - it's too much. They couldn't have kept this hidden from the Feddies."

"But they did. We haven't been bothered."

"Yeah. All the same, I'll be glad to get back home." I pulled her to me and kissed her. Then again. Then - "Not now," she said impatiently. "Please. I want to check some figures -"

"I sort of had figure checking in mind myself," I said. I looked at her to show what figure I had in mind.

"I have. to work. And we've got to make an early start in the morning. Dr. Drury is taking us to the top of the volcano. I want to get some sleep." She pulled away. "Good night, Garrett. I love you."

"Yeah. Sure. I love you to -"

She went into her room and closed the door. They'd given us a concrete blockhouse, with an air lock, and a big main room, and three smaller rooms. There was even running water, hot water in the daytime. I had the bomb put in one of the rooms, and one of my troops was awake and in the blockhouse at all times. Erica thought I was silly; when we first came she wouldn't let it out of her sight, but now she said I was making a fool of myself, and insulting our hosts as well, by insisting on guarding it with our own people rather than let the university staff take care of it.

I thought she was probably right, but the Skipper had made it clear that the damn thing was ours, and we would set it off at the right time and place. I went over to the desk and sat down to take the first watch.

It's soft duty. I told myself. And there's coffee to drink. Relax and enjoy it.

Drury had instruments set up all around the area. Every now and then he'd blow off a dynamite charge and needles would squiggle as the shock waves passed. By feeding the squiggles into a computer he got a picture of the rock and gunk under the volcano. The bomb had to be placed just right so it would crack the rocks that plugged up the lava and gas flow. If everything went right when we blew the weapon, there would be a big gusher of water vapor and gas.

We drove up the side of the mountain the next day. I left Doug and Don Plemmons sitting on the bomb so I could stay with Erica. It took most of the morning to drive up the side of the big mountain, even though the university had blasted out a road years before.

"This one volcano won't do much," Drury told us as we drove up. "But if - no, when - this works we'll have others. I'll show you, up on the rim."

When we reached the top we got out and looked over the edge. The volcano floor was far below. It was flat and smooth. "This was active not a thousand years ago," Drury said. "An instant, geologically speaking. It's still got plenty of pressure underneath. A single bomb should do it. But come look here."

He led the way up a series of steps cut into a big rock at the rim edge. There was a flat place on top where you had a view of the plains all around us. "Look out there," Drury said. He pointed northeast. "We're standing on a little baby, but look at that."

He was pointing to an enormous, cone-shaped mountain. Its base was beyond the horizon, over a hundred miles away, but still it was huge, like Manhattan Island standing on end, ten miles high. "When we set that off, you'll know it! And it's not the biggest we have, either." He pointed northwest. "You can't see it, but over that way is Olympus Mons, the granddaddy of them all. Biggest mountain in the solar system. Fifteen miles high, higher than from the bottom of the deepest sea on Earth to the top of Mount Everest. They could see it from Earth before the spacecraft ever got here. Nix Olympica, they called it. Snows of Olympus. You can see the cloud cover over it."

There were thin white clouds out where he pointed.

"One day we'll wake him up," Drury said. "That will really be something to see."

I still made rounds at night. It seemed silly and I knew it, but I couldn't get over the feeling that an operation this big couldn't be hidden. The Federation still controlled everything in this part of Mars. Even the station owners were careful to hide their revolutionary sympathies. And there might not be very many Feddie cops out here, but there were enough to roll over us.