"That is a pity," he said, with the intonation of a preaching minister.

"But I cannot stop the machinery set in motion...."

"And besides," finished Gray acidly, "you think that if Jill Moulton dies with me, it'll break John Moulton so he won't fight you at all."

His lean hand poised on the switch.

"All right, you putrid flesh-tub. Try and catch us!"

The screen went dead. Gray hunched over the controls. If he could get past them, lose himself in the glare of the Sun....

He looked aside at the stony-faced girl beside him. She was studying him contemptuously out of hard gray eyes.

"How," she said slowly, "can you be such a callous swine?"

"Callous?" He controlled the quite unreasonable anger that rose in him.

"Not at all. The war taught me that if I didn't look out for myself, no one would."

"And yet you must have started out a human being."

He laughed.

The ship burst into searing sunlight. The Sunside of Mercury blazed below them. Out toward the velvet dark of s.p.a.ce the side of a waiting ship flashed burning silver.

Even as he watched, the flare of its rockets arced against the blackness. They had been sighted.

Gray's practised eye gauged the stranger's speed against his own, and he cursed softly. Abruptly he wheeled the ship and started down again, cutting his rockets as the shadow swallowed them. The ship was eerily silent, dropping with a rising scream as the atmosphere touched the hull.

"What are you going to do?" asked Jill almost too quietly.

He didn't answer. Maneuvering the ship on velocity between those stupendous pinnacles took all his attention. Caron, at least, couldn't follow him in the dark without exhaust flares as guides.

They swept across the wind-torn plain, into the mouth of the valley where Gray had worked, braking hard to a stop under the cables.

"You might have got past them," said Jill.

"One chance in a hundred."

Her mouth twisted. "Afraid to take it?"

He smiled harshly. "I haven't yet reached the stage where I kill women.

You'll be safe here--the men will find you in the morning. I'm going back, alone."

"Safe!" she said bitterly. "For what? No matter what happens, the Project is ruined."

"Don't worry," he told her brutally. "You'll find some other way to make a living."

Her eyes blazed. "You think that's all its means to us? Just money and power?" She whispered, "I hope they kill you, Duke Gray!"

He rose lazily and opened the air lock, then turned and freed her. And, sharply, the valley was bathed in a burst of light.

"d.a.m.n!" Gray picked up the sound of air motors overhead. "They must have had infra-red search beams. Well, that does it. We'll have to run for it, since this bus isn't armed."

With eerie irrelevancy, the teleradio buzzed. At this time of night, after the evening storms, some communication was possible.

Gray had a hunch. He opened the switch, and the face of John Moulton appeared on the screen. It was white and oddly still.

"Our guards saw your ship cross the plain," said Moulton quietly. "The men of the Project, led by Dio, are coming for you. I sent them, because I have decided that the life of my daughter is less important than the lives of many thousands of people.

"I appeal to you, Gray, to let her go. Her life won't save you. And it's very precious to me."

Caron's ship swept over, low above the cables, and the grinding concussion of a bomb lifted the ship, hurled it down with the stern end twisted to uselessness. The screen went dead.

Gray caught the half stunned girl. "I wish to heaven I could get rid of you!" he grated. "And I don't know why I don't!"

But she was with him when he set out down the valley, making for the cliff caves, up where the copper cables were anch.o.r.ed.

Caron's ship, a fast, small fighter, wheeled between the cliffs and turned back. Gray dropped flat, holding the girl down. Bombs pelted them with dirt and uprooted vegetables, started fires in the wheat. The pilot found a big enough break in the cables and came in for a landing.

Gray was up and running again. He knew the way into the explored galleries. From there on, it was anybody's guess.

Caron was brazen enough about it. The subtle way had failed. Now he was going all out. And he was really quite safe. With the broken cables to act as conductors, the first thunderstorm would obliterate all proof of his activities in this valley. Mercury, because of its high electrical potential, was cut off from communication with other worlds. Moulton, even if he had knowledge of what went on, could not send for help.

Gray wondered briefly what Caron intended to do in case he, Gray, made good his escape. That outpost in the main valley, for which Ward had been heading, wasn't kept for fun. Besides, Caron was too smart to have only one string to his bow.

Shouts, the spatter of shots around them. The narrow trail loomed above.

Gray sent the girl scrambling up.

The sun burst up over the high peaks, leaving the black shadow of the valley still untouched. Caron's ship roared off. But six of its crew came after Gray and Jill Moulton.

The chill dark of the tunnel mouth swallowed them. Keeping right to avoid the great copper posts that held the cables, strung through holes drilled in the solid rock of the gallery's outer wall, Gray urged the girl along.

The cleft his hand was searching for opened. Drawing the girl inside, around a jutting shoulder, he stopped, listening.

Footsteps echoed outside, grew louder, swept by. There was no light. But the steps were too sure to have been made in the dark.

"Infra-red torches and goggles," Gray said tersely, "You see, but your quarry doesn't. Useful gadget. Come on."

"But where? What are you going to do?"

"Escape, girl. Remember? They smashed my ship. But there must be another one on Mercury. I'm going to find it."

"I don't understand."

"You probably never will. Here's where I leave you. That Martian Galahad will be along any minute. He'll take you home."