Doug added, "And it would take an hour of pre-breathing before you could get into a suit without giving yourself the bends."

"Besides," the Russian said, "if the EVC goes down, the suits will only prolong your misery for a few hours more."

"Very encouraging," Zimmerman said loudly as he stepped through the control center's entrance. "I don't suppose you have suits my size anyway."

They all turned to see the fat old professor walking toward them as carefully as a man negotiating a minefield. Zimmerman's gray three-piece suit looked rumpled, but there was no sign of fear in his fleshy face. He looked more annoyed than afraid.

"I told you to stay in your quarters," Doug said. "How did-"

"You expect me to sit in that coffin of a cell, all alone? Never! If I am to die, it will be in company."

"But the hatches."

"Bah! Obviously I learned how to open them."

"You shut them behind you, I hope."

Anson said, "They close automatically, don't worry about it."

"So what is the problem?" Zimmerman asked.

Doug swiftly explained. The old man's face went gray.

"Cut off our air? He must be a madman!"

Without looking at his mother's reaction, Doug said, "We've got to get in there and stop him before he knocks out all the pumps and kills us all."

Brudnoy said, "The security team said the hatch to the EVC was sealed shut. They started to force it open manually but the air pressure kept on dropping in the tunnel and they had to get out."

"He's got himself barricaded in there," said Doug.

Anson said, "At least we got everybody out of the garage and tunnel four. No casualties."

"Yet," Brudnoy muttered.

"But even if he stops the pumps," Joanna asked, "won't the air recycling equipment keep going?"

"Won't do us a rat's ass worth of good if the pumps shut down," Anson replied, brow's knitted. "If he shuts down all the freakin' pumps, we'll all be asphyxiated within a couple of hours."

"But you said we had backups..."

"They'll scrub of the CO2 for a few hours," Anson said flatly. "They were only meant for short-term emergencies, not to replace the main system indefinitely."

"What can we do?" Joanna pleaded.

"I've got to get in there and stop him," said Doug.

"You?" Zimmerman asked.

"Me."

"But how?"

Turning to Anson, Doug asked, "Is there any other way into the EVC besides the hatch from the tunnel?"

She shook her head gloomily.

Doug asked, "What about the air ducts?" He turned back to the big electronic map. "All the air ducts in the base lead into the EVC, sooner or later. Maybe I can crawl through one-"

"Only if you are the size of a little mouse," Brudnoy said morosely. "The ducts are too small for you."

"There must be some way to get in there."

Brudnoy scratched at his beard, staring at the big wall map. Then he reached up and traced a finger along a ghostly gray line that reached from the EVC to the edge of the base, at the face of the ringwall mountain. It branched four times, once into each of the base's main tunnels.

"The plasma torch vents," he murmured.

"What?"

"When we started excavating these tunnels," Brudnoy explained, "we vaporized the rock with plasma torches."

"Everyone knows that," Joanna snapped.

"Yes, dear lady. But everyone forgets that we vented the vaporized rock outside through large ducts."

"Big enough for a man to crawl through?" Doug asked eagerly.

Brudnoy nodded. "We made them big so the vapors could get out quickly and dissipate into the vacuum outside."

"Terrific!"

"But those vents have, been sealed off for years," Anson pointed out.

"The seals were very simple, very primitive, if I recall correctly," said Brudnoy, furrowing his brow. "Nothing more than a series of airtight partitions every hundred meters or so. And they can be opened and closed from here in the control center, once you call up the proper program."

"That program must be ancient, Anson snapped.

"As old as I am, do you think?" countered Brudnoy, with a smile.

Doug whirled to the nearest empty console and began working its keyboard even before he pulled up a chair to sit in.

"Come on, Lev," he called. "Help me find it."

Brudnoy leaned over Doug's shoulder as the screen scrolled through several menus. Finally, a schematic of the vent system came up.

"Okay!" Doug said, nearly shouting. "I can crawl through the vent that runs along the tunnel here, work my way into the central vent, and then come down into the EVC."

"Is there air in the vents?" Joanna asked.

"Yep," said Anson. "Same pressure as the rest of the base, too."

"Then I can work my way through without a problem," Doug said.

"You'll have to get through the partitions," said Brudnoy.

"Those partitions haven't been opened in nearly twenty years, Anson said.

"They're controlled from here, though, aren't they?" Doug asked.

She nodded, but warned, "Some of 'em might be sealed shut. Dust gets into everything, y'know."

I'll need some power tools, then."

Nodding, Brudnoy said, "The two of us should be able to pry the hatches open, even if they don't respond to the controls."

Doug did not reply to the Russian. Turning to Anson, he said, "Get a repair team suited up and working on the hatch that Greg sealed. Start them prebreathing now. We're going to need every second we can squeeze out. Come on, we don't have any time to waste!"

"Wait a minute," Anson said. "If we pry that hatch open, the whole EVC's gonna lose its air. It'll go down to the pressure in tunnel four," she snapped her ringers, "like that.'

"Can't be helped," said Doug.

"Yeah, but what if you're in the EVC when they break through?"

With a shrug, Doug repeated, "Can't be helped. We have to do everything we can, as quick as we can."

"But the risk-"

Tell the crew working on the hatch to bring some breathing masks from the infirmary. If they can get them on us fast enough we'll be okay."

"You're taking a helluva chance," Anson said.

"What's the alternative?" Doug challenged. "Let my brother kill all of us? Let Moonbase die?"

Joanna stepped up to her son. "Doug, I can't let you do this. It's too dangerous."

"You can't stop me, Mom."

"Douglas-"

"I'm not going to let him destroy Moonbase," Doug said firmly. "He tried to once before, remember? I'm not going to let him get away with it."

"Your life is worth more than Moonbase," Joanna said.

He locked his gray-green eyes with hers. "No, it isn't," Doug said flatly. "Moonbase is more important than any of us."

"Not to me."

"It is to me," Doug said. Then he added, "He's trying to kill you, too, you know."

Joanna's mouth opened, but no sound came out Doug started for the door.

"Aren't you going to at least put on a spacesuit?" Joanna called after him.

"No time, Mom! I've got to get to Greg as fast as I can."

The bends, Bianca Rhee thought, trying to fight down the panic surging through her. Breathing the low-pressure air in the suit tank means that the nitrogen in my cells will bubble out and cause all kinds of trouble.

How long do I have? she asked herself as she hurried across the emptied garage toward the nearest hatch to a tunnel. Minutes? Seconds?

She reached the hatch to tunnel four, fumbled with the electronic keypad in her eagerness to get it open, and finally managed to get her gloved finger on the proper button. The hatch slid-open and she stepped into the little chamber between the outer and inner hatches that served as an airlock.

Okay, she told herself shakily. So far so good.

She got the inner hatch open and, with a sigh of relief, slid up the visor of her helmet.

And choked. She couldn't catch her breath. No air! she screamed silently as she slammed her visor down again. They've pumped the air out of this tunnel! What if they've pumped the air out of all of them?

A sharp needle of pain seared her chest. Got to try the next tunnel. She stumbled through the airlock again, back out into the garage, and headed for the hatch to tunnel three. ~ Her legs gave way before she reached it. Agonizing pain flared through her. She felt as if she was being electrocuted. Or burned at the stake.

Jesus, Mary and Joseph, she cried to herself. It hurts! Christ! Oh Christ, Christ, Christ it hurts!

Greg got to his feet slowly and admired his handiwork. What had been a set of air pumps was now a shambles of disconnected parts scattered across the cold rock floor of the EVC.

"That's one," he said, puffing slightly.

Melissa stood beside him, her cool gray jacket smeared with grime, her hands greasy, knuckles skinned from banging them as she tried to help Greg.

"Let's get the next one," she urged.

"Give me a minute," Greg said, stretching his arms over his head. He was unaccustomed to so much intense physical exertion.

"They'll be trying to get in here again," she warned.

Greg gave her a knowing smile. "Not yet. I pumped down the air pressure out in the tunnel before taking the pump apart. They can't breathe the thin stuff out there now."

"But they have spacesuits, don't they?"

"Sure. But it takes an hour of prebreathing before you can get into a suit. Unless you want to die of the bends."

"Prebreathing?" Melissa asked. "Bends?"

"Never mind," Greg snapped. "Let's get to work on the next set of pumps."

"Good!"

"Four tunnels," Greg said as he stooped to gather his tools. "Each one has its own set of air pumps, including backups. Triple and quadruple redundancy." He laughed, a brittle sound that rang off the stone walls. "A lot of good it's going to do them!"

"Will we have time to do them all?" Melissa asked.