He said mildly to the blank screen, "Your first wave had to surrender to us, colonel."

Giap seemed to hesitate. Then he replied, "It would be quite easy for us to cut off your electrical power supply."

There it was, at last. Doug almost felt relieved. "Not as easy as you may think, Colonel," he replied. "We've buried secondary lines to take over if the primaries are cut."

"We have sensors that will find all the lines."

"And we have your first wave's weapons," said Doug, putting some steel into his voice. "Don't force us to use them."

"So we will have a firefight? I believe my troops have more guns—and more ammunition for them."

"How much oxygen do they have?" Doug asked.

"What do you mean?"

"How long can you remain out on the crater floor, colonel? Remember, we have some of your shoulder-fired missiles now. We can hit your tractors."

"We have all the logistics we need. You should surrender to me and avoid useless bloodshed."

Before Doug could reply, Gordette leaned over his shoulder and pointed to the screen showing the floor of the crater. "There's some activity out there."

Doug glanced at the screen. "Wait a moment, Colonel," he said. I'll be back with you in a few minutes."

Cutting the connection to the Peacekeepers, Doug punched up a request to rerun the outside camera view.

"Look," Gordette pointed. "Over there."

A dozen spacesuited figures marched purposefully toward the main airlock. As they approached they walked out of the camera's field of view.

"What do the cameras inside the garage show?"

Checking on them, Doug and Gordette saw that the view from inside the garage did not show the dozen troopers at all.

"They stopped outside, off to one side of the main airlock," Doug said.

"Why?" asked Gordette.

"I'll try to find out," said Doug.

Colonel Giap was alone in the tractor's cab now. Through his binoculars he could see a squad of his troopers helping the Sacred Seven up an aluminum ladder they had placed against the face of the mountain, just to the side of Moonbase's main airlock. They were struggling to open the square hatch that led into the old plasma vents.

Giap had studied Moonbase's layout until he knew it as well as the face of his beloved mother. The plasma vents were from Moonbase's earliest days, when the builders were excavating tunnels by boiling away the rock with high-temperature plasma torches. The vents let the ultra-hot vapors blow out into the vacuum outside. The vents had not been used, as far as Giap knew, in years. Yet they threaded through the rock above the main corridors of Moonbase. Crawling through them, a man could reach every critical part of the base.

The volunteers will penetrate the base before the rebels know they are being infiltrated. Their first warning will be when the fanatics begin to blow themselves up. Themselves, and every crucial part of Moonbase.

"Colonel Giap?" Stavenger's voice sounded in his earphones.