“What about tunnel four?” Doug asked. “That’s the tunnel that leads into the EVC, isn’t it?”

“Yeah, right. He must’ve shut down the pumps, I guess. Or maybe turned off the air-circulating fans. It doesn’t take much.”

“What is he trying to do?” Brudnoy asked.

“Commit suicide,” Joanna replied without an instant’s hesitation.

“And take all of us with hint?” Anson almost snarled the words.

Joanna nodded silently.

Doug asked, “Has anybody been able to make contact with him?”

Anson shook her head. “He doesn’t answer, not even the paging system. And he must’ve knocked out the surveillance cameras somehow, we can’t get a picture from inside theEVC.”

“Damn!”

Doug saw that the consoles were fully manned; tight-lipped technicians sat at the monitor screens, headsets clamped to their ears, fingers running over their keyboards as they checked every system in Moonbase.

In the control center’s air of quiet frenzy, Anson had naturally, automatically taken charge.

“He’s trying to knock out the whole base,” she said, thinking aloud. “Already blown out the garage and tunnel four’s down below safe minimums. It’s only a matter of time before he gets the rest of us.”

“What can we do to stop him?” Joanna asked, sounding a bit frantic.

“First things first,” said Anson. Turning, she marched to one of the consoles and spoke to the technician seated there. “Activate all the emergency air filtration systems. And get a squad of safety people to manually check them.”

Doug saw the question in his mother’s eyes. “Backup systems,” he explained, “to filter the carbon dioxide out of the air. Even if Greg shuts down the main recycling equipment, the backups will keep our air breathable.”

“For how long?” Joanna asked.

Brudnoy looked at her with sad eyes. “A few hours,” he said softly. “At most, a few hours.”

“Shouldn’t we get everyone into spacesuits, then?” Joanna suggested.

“There aren’t enough suits for everyone,” Brudnoy countered.

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.”