"I'm glad one of us knows what I'm doing…"

But Lona was frowning at the meter, frowning and taking out her keypad. She punched in the data displayed on the circuit and said, "Red lead to contact B, Granpa, and blue lead to contact H."

So it went, Whitey placing the probes where she told him, she frowning at the readout and punching data into her keypad. He began to think she wasn't really aware of him any more, was just using him as a sort of voice-activated servomechanism.

Well, at least it was some sign of life.

Finally, she straightened up with a sigh and said, "That's all. We've checked every circuit. There's nothing more here for me."

Whitey fastened the access panels back in place, listening to her words echo inside his head in secret, sad satisfaction. But he kept his face solemn, a little exasperated, and glanced at the time display built into his faceplate. "Not a minute too soon; I promised Herman forty-five minutes, and it's been fifty. Come on, child, let's go—and counterclockwise, please—let's not get our tails snarled."

"Hm? Oh sure, Gran'pa." and she followed him out, frowning, deep in thought.

Whitey fastened the trapdoor back in place and took her hand, turning back toward the burro-boat. "Learn anything?"

"Uh-huh." She nodded. "It's in perfect working order."

"What?" Whitey jerked to a stop, staring down at her.

"It is, Gran'pa." She sounded a little bit afraid, as though she might have done something wrong. "We could power it up, and it could put out a dome."

Whitey kept a firm hold on Lona's hand, but whether it was for her stability or his, he couldn't have said. His mind, at least, was in a whirl. "How could that generator have failed if it was in perfect working order?"

"Somebody turned it off."

He looked down at Lona, startled.

She looked up at him out of wide, grave eyes. "Somebody had to have turned it off, Gran'pa. It's the only way."

"But it took me a full week, a letter testifying need, and a dozen forms to five different offices, to get the combination for that lock—and that's when it wasn't operating! How could anybody even have gotten to it?"

"I don't know," Lona said, "but somebody did."

Whitey froze as a thought hit him. "Child," he said slowly, "I didn't see a power switch in there."

Lona stopped dead with one foot in the air. Then, carefully, she put it down and nodded. "You're right, Gran'pa. There wasn't any."

"Well, if there's no switch, who could turn it off?"

"The computer," she said.

"But that means somebody programmed it to turn off the field!"

She was quiet for a moment, then asked, "Couldn't it have developed a glitch?"

"Chances are obscenely low, child! But who could have reached the computer?"

"Gotta find out," she mumbled, and turned away toward the boat.

Whitey came out of his stupefaction and hurried after her. Abstracted as she was, she was apt to bump into a sharp piece of junk and tear her suit—so he was in the perfect position when he saw the drilling laser on the boat's bow turn toward them.

He hurled himself at her in a long, flat dive that caught her hips right across his shoulder and carried her into cover behind a house as the laser bolt spattered molten rock where she'd been standing. She cried out, of course, and Whitey snapped, "Quiet!" His brain revved into high gear, picking illusion as their only defense and pegging the manner of it instantly. "Now get in there, and lie absolutely still!" he snapped, cradling her in one arm and holding the other forefinger up in front of his faceplate. Helmet or not, she recognized the "Sh!" sign and squeezed her lips shut, eyes wide, stiff as a fashion doll.

The stiffness didn't help any, but he managed to dodge around a corner, weave a right-angled "S" around three houses, find a broken window that he could reach in and unlock, then opened the casement and pushed Lona through. She grabbed the nearest table and crouched under it, wide-eyed. Whitey pointed downward, hoping she understood that he wanted her to go down into the cellar, and very much aware that whoever had fired on them must be listening to their radio frequency. Then he turned away, dodging and weaving as far from his granddaughter as he could, eyeing the black sky with trepidation, knowing the burro-boat must be aloft and hunting.

And it was. Fire spat down out of sun-glare—right into the first house he'd hidden behind. He felt a glow of satisfaction—the would-be murderer had blasted the spot where Whitey had said he was hiding Lona. Because the gunman had been eavesdropping on their suit frequency, of course, and thought Whitey had stuffed Lona into hiding at that first house.

Only you can't "blast" something with a drilling laser—the beam is too narrow, and the power's too low. Constant, but low—and the blast was still walking down out of the sky, stabbing the house again, and again, and again.

How long can he keep that up? Whitey wondered, and the idea blossomed. Because a laser used a lot more power than the bursts of acceleration needed in the Belt, and maybe Herman had been telling the truth, maybe he really was that low on fuel.

But he had to keep that idiot in the boat firing. He'd be done with that house very soon—and he'd figure Whitey wasn't in it.

Hatred seared through Whitey, hatred at any man who could try to burn up a child like that. He put his feet against the nearest wall and shoved off, darting from house to house, looking for something, anything, to keep the man shooting.

And cover—to keep the murderer from shooting him.

A blank wall loomed in front of him—a warehouse. The door was open, of course—why lock anything, when you know all your neighbors? He ducked in and breathed a sigh of relief, then pushed himself over to a window on the long side, and looked out at the square with the park at its far end.

The boat was there, right enough, hovering fifty feet up, high enough to see any movement, low enough to be within range—and not firing.

But if it was in range to shoot at them, it was in range to be shot. Whitey toggled his helmet lamp and cast about frantically, looking for a weapon, some kind of weapon, or at least something that would make a big explosion of light…

And there they were, racked against the side wall, right next to the door he'd come in by, twenty rifles, plugged in to recharge. Whitey hopped over to them, blessing the Belter's inherited sense of caution—the Asteroid Belt detachment of Marines had kept the peace well for the last fifty years, but there were still old-timers around who could tell hair-raising stories of the pirates and claim-jumpers who had riddled the asteroids almost from the day they were opened to prospecting, and had even made a fair bid to establish their own tyranny. The pirates were gone, but it had become traditional to keep a rifle handy.

Very handy. Whitey unplugged one, blessing his luck and hoping the current was still running. No reason why it shouldn't be—the planetoid had been powered by a fission generator, which was good for fifty years. No reason to have shut it down, either, with fissionables so plentiful out here. He picked out a rivet on the far wall for a target, set the rifle on low power, sighted, and squeezed.

The bolt of energy spattered a circle of molten metal, just above and to the left of the target.

Whitey's heart sang as he corrected the sights and fired again. This time the rivet disappeared, and he leaped back to the window, setting the rifle to full power, aiming at the burro-boat, breathing out, and squeezing the firing patch.

A flower of fire lit the boat's bow.

It was turning toward him even as Whitey was squeezing off his second shot. Whoever the pilot was, he recognized a real weapon when he saw its bolt, and knew he had to put it out of action fast. The boat shot toward the warehouse as the drill bored down, punching through the warehouse roof.