"I couldn't sleep," said Gray amiably. "He was telling me bedtime stories." Jill Moulton was lovely, he couldn't deny that. Lovely, but not soft. She gave him an idea.

Moulton's jaw clamped. "Cut the comedy, Gray. Are you working for Caron of Mars?"

Caron of Mars, chairman of the board of the Interplanetary Prison Authority. Dio had mentioned him. Gray smiled in understanding. Caron of Mars had sent him, Gray, to Mercury. Caron of Mars was helping him, through Ward, to escape. Caron of Mars wanted Mercury for his own purposes--and he could have it.

"In a manner of speaking, Mr. Moulton," he said gravely, "Caron of Mars is working for me."

He caught Ward's sharp hiss of remonstrance. Then Jill Moulton stepped forward.

"Perhaps he doesn't understand what he's doing, Father." Her eyes met Gray's. "You want to escape, don't you?"

Gray studied her, grinning as the slow rose flushed her skin, the corners of her mouth tightening with anger.

"Go on," he said. "You have a nice voice."

Her eyes narrowed, but she held her temper.

"You must know what that would mean, Gray. There are thousands of veterans in the prisons now. Their offenses are mostly trivial, but the Prison Authority can't let them go, because they have no jobs, no homes, no money.

"The valleys here are fertile. There are mines rich in copper and pitchblende. The men have a chance for a home and a job, a part in building a new world. We hope to make Mercury an independent, self-governing member of the League of Worlds."

"With the Moultons as rulers, of course," Gray murmured.

"If they want us," answered Jill, deliberately missing the point. "Do you think you have the right to destroy all we've worked for?"

Gray was silent. Rather grimly, she went on.

"Caron of Mars would like to see us defeated. He didn't care about Mercury before radium was discovered. But now he'd like to turn it into a prison mining community, with convict labor, leasing mine grants to corporations and cleaning up big fortunes for himself and his a.s.sociates.

"Any trouble here will give him an excuse to say that we've failed, that the Project is a menace to the Solar System. If you try to escape, you wreck everything we've done. If you don't tell the truth, you may cost thousands of men their futures.

"Do you understand? Will you cooperate?"

Gray said evenly, "I'm my own keeper, now. My brother will have to take care of himself."

It was ridiculously easy, she was so earnest, so close to him. He had a brief kaleidoscope of impressions--Ward's sullen bewilderment, Moulton's angry roar, Dio's jerky rise to his feet as the guards grabbed for their guns.

Then he had his hands around her slim, firm throat, her body pressed close to his, serving as a shield against bullets.

"Don't be rash," he told them all quietly. "I can break her neck quite easily, if I have to. Ward, unlock that door."

In utter silence, Ward darted over and began to spin the dial. At last he said, "Okay, c'mon."

Gray realized that he was sweating. Jill was like warm, rigid marble in his hands. And he had another idea.

"I'm going to take the girl as a hostage," he announced. "If I get safely away, she'll be turned loose, her health and virtue still intact.

Good night."

The clang of the heavy door had a comforting sound behind them.

The ship was a commercial job, fairly slow but st.u.r.dy. Gray strapped Jill Moulton into one of the bucket seats in the control room and then checked the fuel and air gauges. The tanks were full.

"What about you?" he said to Ward. "You can't go back."

"Nah. I'll have to go with you. Warm her up, Duke, while I open the dome."

He darted out. Gray set the atmosphere motors idling. The dome slid open, showing the flicker of the auroras, where areas of intense heat and cold set up atmospheric tension by rapid fluctuation of adjoining air ma.s.ses.

Mercury, cutting the vast magnetic field of the Sun in an eccentric orbit, tortured by the daily change from blistering heat to freezing cold in the thin atmosphere, was a powerful generator of electricity.

Ward didn't come back.

Swearing under his breath, tense for the sound of pursuit in spite of the girl, Gray went to look. Out beyond the hangar, he saw a figure running.

Running hard up into the narrowing cleft of the valley, where natural galleries in the rock of Mercury led to the places where the copper cables were anch.o.r.ed, and farther, into the unexplored mystery of the caves.

Gray scowled, his arrogant Roman profile hard against the flickering aurora. Then he slammed the lock shut.

The ship roared out into the tearing winds of the plain. Gray cut in his rockets and blasted up, into the airless dark among the high peaks.

Jill Moulton hadn't moved or spoken.

Gray snapped on the s.p.a.ce radio, leaving his own screen dark. Presently he picked up signals in a code he didn't know.

"Listen," he said. "I knew there was some reason for Ward's running out on me."

His Indianesque face hardened. "So that's the game! They want to make trouble for you by letting me escape and then make themselves heroes by bringing me in, preferably dead.

"They've got ships waiting to get me as soon as I clear Mercury, and they're getting stand-by instructions from somebody on the ground. The somebody that Ward was making for."

Jill's breath made a small hiss. "Somebody's near the Project...."

Gray snapped on his transmitter.

"Duke Gray, calling all ships off Mercury. Will the flagship of your reception committee please come in?"

His screen flickered to life. A man's face appeared--the middle-aged, soft-fleshed, almost stickily innocent face of one of the Solar Systems greatest crusaders against vice and crime.

Jill Moulton gasped. "Caron of Mars!"

"Ward gave the game away," said Gray gently. "Too bad."

The face of Caron of Mars never changed expression. But behind those flesh-hooded eyes was a cunning brain, working at top speed.

"I have a pa.s.senger," Gray went on. "Miss Jill Moulton. I'm responsible for her safety, and I'd hate to have her inconvenienced."

The tip of a pale tongue flicked across Caron's pale lips.