Moments later, the two groups of Masters converged at the gate, two from one direction and five from the other.

"After them!" commanded Placer. "But stay together. We'll have to try to hunt them down in the vats, and maybe the Toughs can help us, but we don't want to get separated so they can pick us off one by one."

"Wait, Placer, there's something you ought to know," said one of the two Masters who had come from the direction of the conference room. "Greyde called out a few minutes ago to tell us he had word from Vidonati in the control room. Those groundcars that were hanging around had attacked one of the entrance buildings."

"Space!" growled Placer. "There must be a conspiracy involved here somewhere. We'd better stay up here, then."

He pulled the lever beside the gate to the ramp, and it rumbled down and crashed into place.

"At least, those two are trapped below," he said with satisfaction. "We can hunt them down at our leisure when we've repelled this attack from outside. If we can take them alive, I'm of a mind to make them pay well for their responsibility in our losing all our experimental Jellies."

The seven of them went on to the conference room, picking their way among the bodies of the Jellies. Placer took over the intercom from Greyde.

"Vidonati, this is Placer," he said. "What's the situation?"

"The groundcars attacked the south building," replied Vidonati. "They moved in and concentrated all three car beams on the airlock and burned it through. I counted nine men in marsuits who left the groundcars and went into the building. Of course, as soon as they started blasting the airlocks, I closed the emergency barrier to block off the downward ramp."

"Obviously, since we still have air in the place," commented Placer dryly. "You'd better call Mars City and get them to send help."

"I've already done that," said Vidonati. "A jet squadron's on its way."

"Good," said Placer. "They can be here in about five hours, and it will take those rebels, or whoever they are, two or three times that long to burn through one of the emergency barriers, even if they blast an opening and bring their groundcars into the building to bring the groundcars' big guns on it."

"Should I stick it out here, or seal all the barriers and come below?" asked Vidonati. The control room was in the north building.

"Stay up there so you can report on what they're doing, unless they start to move toward that building," instructed Placer. "If they do, seal the other emergency barriers at once and come below. We can switch to the emergency radio down here to keep in touch with the task force from Mars City, and just wait it out underground until they clean up these rebels."

"Good enough," agreed Vidonati. "I won't take any chances."

In the vats below, Dark and Maya made their way to Old Beard's hideout, their heatguns ready, keeping a sharp lookout for Toughs. They reached it without incident.

Dark looked sadly around the little recess beneath the tangled vegetation, where Old Beard had concealed himself successfully so long from both Toughs and Masters. He had hoped that this reunion with his father would mean many years of companionship between them, once they were free of the Canfell Hydroponic Farm and had found a haven in the Icaria Desert.

But he knew that Old Beard had died in an act that had great meaning to him, a savage revenge that had wiped out the bitter memory of the loss of his wife and had repaid him for twenty-five long years of exile. Old Beard had died nobly.

Dark picked up one of the smaller marsuits.

"We don't know what's going to happen above, and we can't help much by staying inside, now that we can't hold that corridor and bottle them up in a room until Cheng and the Phoenix break in," said Dark. "We'd best get up to one of the exit buildings, get out through the airlock and get picked up by one of the groundcars. I don't need a marsuit, but you can put that on as soon as we get above in the building."

"Have you been in telepathic touch with Cheng?" asked Maya.

"Yes. They've already broken into the south building. That's the one I came through when I left for Ultra Vires and when I came back. But the Masters let down a heavy emergency barrier on the ramp when they attacked the airlock, and we wouldn't be able to get through that. There's a ramp near here that Old Beard told me opens onto the north building. We'll go there, and I'll send a call to Cheng to move over and meet us there."

Dark sent out a call to Cheng and received an acknowledgement. He and Maya started for the ramp, unaware that the building which was their goal housed the farm's control room, and the watching Vidonati.

Above, a few moments later, Vidonati called Placer on the intercom.

"Placer, they've come back to the groundcars and turned them in this direction," said Vidonati. "I'm going to let down the barriers on the ramps from the east and west buildings, sabotage the controls so they can't raise them again, and come on down. I'll lower the barrier to this building from inside, as soon as I get past it on the ramp."

"All right," said Placer. "We'll start getting the emergency radio in operation down here. Do a good job, but do it fast, and don't get caught up there by the rebels blasting the airlock."

"I won't," promised Vidonati. "It'll only take me a few minutes, and I can be down the ramp before they can focus their beams on the airlock."

In the lead groundcar, as the three of them wheeled around and headed slowly for the north building, Cheng turned to one of his companions with a frown.

"I've been trying to get through telepathically to Dark, but I can't reach him," said Cheng. "He didn't give any instructions for getting into the building, but they seem to have locked these airlocks by remote control so they can't be operated. We'll have to blast this one as we did the other one, because I don't imagine Dark will be able to open it from inside. He seemed in rather a hurry to be picked up."

Dark and Maya hurried up the ramp toward the north building. Dark had been concentrating too heavily on finding his way through the vats to receive Cheng's telepathic call.

They passed the barred gate that opened into the corridors of the upper level, and a few moments later reached the top of the ramp and the gate to the north building. Dark had been prepared to open this by telekinesis but, to his surprise, it was already open.

They passed through it and emerged into the north building.

Dark had never seen one of the ground-level buildings in daylight, as both times he had passed through the south building it had been night. He looked around the place curiously as they entered.

It was about fifty feet square, bare except for the low, hard bunks on which the Toughs slept at night. On three sides of it were windows, now closed with heavy steel shutters. The airlock was across the room, opposite the ramp entrance. The fourth wall was blank, and apparently shut off a room at the end, because there was a closed door in the center of it.

They moved out into the room, and Dark said:

"Slip into your marsuit, and we'll go out the airlock. I told Cheng to bring the groundcars over this way, and they ought to be ready to pick us up by the time we get out."

"I don't see why we didn't stay down in the vats until the Phoenix break in," said Maya. "We were well hidden down there, and there might have been some way we could have helped the Phoenix from inside."

"Primarily because I'm not sure now that the Phoenix can break in," answered Dark. "I didn't know about that heavy emergency barrier the Masters let down on the south ramp, and I was surprised and relieved to find they hadn't dropped one on this ramp, too. If they had, we'd have been trapped below. If they have those barriers on all four ramps, the Phoenix can't stay around long enough to burn through them, because the Masters have probably already called for help from Mars City."

Maya had laid her marshelmet down on one of the bunks, and was pulling the marsuit on over her tunic and trousers.

The door at the other end of the room opened, and a man emerged, a heatgun in his hand.

Vidonati stopped in his tracks, startled, at the sight of Dark and Maya. Dark grunted in surprise, and reached for his heatgun.

Even as Dark freed his weapon, Vidonati fired. The beam missed them, melting away the top of Maya's marshelmet and setting the bunk aflame. Then, as the beam of Dark's gun swung toward him, Vidonati ducked precipitately back into the control room.

"He got your marshelmet!" exclaimed Dark. "We're going to have to go in and flush him out of there, and just hope there's another marsuit in there, before we can open the airlock."

Heatgun in hand, Dark started for the door of the control room, Maya at his heels.

It was then that the Phoenix, the three groundcars drawn up with their heavy guns focused, blasted the airlock of the north building. In seconds, the airlock was burned through.

There was no emergency barrier down on this ramp. The heavy, Earth-pressured air of the north building whistled out into the desert. As from a punctured balloon, the pressured atmosphere of the entire Canfell Hydroponic Farm rushed after it, roaring up the ramp, in a moment stripping the vats, the upper level and the north building.

Caught in the tornadic blast, Dark could only cling to a bolted-down cot with one hand, and hold onto Maya around the waist with the other. As the pressure dropped precipitately and oxygen no longer touched his lungs, he could actually feel his alternate metabolism shifting into gear, he could feel his breathing stop and the glow of solar energy begin to spread through his body.

As the wind faded and died, Dark released Maya and rose exultantly to his feet. Down below, he knew, Nuwell and the Masters were gasping out their lives in the thin air, like beached fish. Their recent attacker, Vidonati, lay half out of the door of the control room, his hands clutching convulsively at the floor.

"That's not the way I'd planned it, but it's just as good!" Dark exclaimed. "We've taken the farm!"

Then he remembered. Maya had no marshelmet!

Appalled, struck to the heart, he turned in his tracks.

Maya was standing behind him, calmly trying to rearrange her raven hair, tangled by the raging rush of wind.

"What's the matter?" she asked quietly, becoming aware of Dark's intent gaze.

"Maya! You don't have a helmet on! Are you breathing?"

She was silent for a moment, apparently examining herself.

"Why, no, I don't believe I am," she replied, just as calmly.

"How can you ...? Wait a minute!"

Dark sent his mind into the invisible. His probing thoughts fled over desert and lowland, seeking. They found the Martian, Qril, and he recognized that Qril responded immediately.

Qril, how is it that Maya is able to live in the Martian atmosphere without breathing? asked Dark telepathically.

She is as you, replied Qril. When she was a child, living among the Martians, we altered her physiological and genetic structure so that she, also, is able to utilize solar energy and exist without oxygen.

Why didn't you tell me this before, at Ultra Vires? demanded Dark.

You did not ask, replied Qril, and the mental contact faded out.

Dark turned to Maya, his face alight.

"Darling," he said, "our children will need no embryonic alterations. They will be born as we are, able to live under Martian conditions. And never again will either of us ever have to wear a marsuit!"

He felt the questing touch of Cheng's mind.

Cheng: Are you there, Dark?

Dark: Here.

Cheng: Are you all right?

Dark: We're both fine! We're coming out. Then we'll take off at once for the Icaria Desert, before the Mars City task force gets here.

He and Maya walked hand in hand through the blasted airlock. The three groundcars were there, waiting.

The two of them stood for a moment, before getting aboard the groundcars, and looked out together across the red desert toward the sinking sun.

Death? Desolation? No, not for them. This was life, and free, bleak beauty, for them and for their children.

The future of Mars was theirs.