In the physically magnetic sense, he could cling for hours to any metallic surface, or at will propel himself about or hang suspended between any two or more metallic objects. As to his personality, he was equally magnetic, for wherever Denver took him he attracted curious stares and comments. Most people have never seen a moondog. Such creatures, found only on the moons of Saturn, are too rare to be encountered often as household or personal pets.

But Tod Denver had won Charley in a crap game at Crystal City; and thereafter found him both an inseparable companion and exasperating responsibility. He had tried every available means to get rid of Charley, but without success. Either direct sale or horse-trade proved useless. Charley liked Denver too well to put up with less interesting owners so Charley always came back, and nearly always accompanied by profanity and threats. Charley was spectacular, and a monstrous care but Denver ended by becoming fond of the nuisance. He would miss the radiant, stupid and embarrassingly affectionate creature.

Charley had currently burned out a transformer by some careless and exuberant antic; hence the mutual doghouse. Scolding was wasted effort, so Denver merely sighed and made a face at Charley.

"Mad dogs and Martians go out in the Lunar sun," he sang as a punishment. Charley recognized only the word "dog" but he considered the song a personal insult; as if Denver's singing were not sufficient punishment for a minor offense. Charley was irritated.

Charley's iridescence flickered evilly, which was enough to short-circuit two relays and weld an undetermined number of hot switches. Charley's temper was short, and short-circuiting all electrical units within range was mere reflex.

Tod Denver swore nobly and fluently, set the controls on automatic-neutral and tried to localize the damage. But for Charley and his overloaded peeve, they would have been in Crystal City inside the hour.

So it was Charley's fault, of course; all of it....

t was beyond mere prank. Denver calculated grimly that his isolated suit would hold up less than twenty minutes in that noon inferno outside before the stats fused and the suiting melted and ran off him in droplets of metal foil and glass cloth. The thermal adjustors were already working at capacity, transmitting the light and heat that filtered through the mirror-tone hull into stored, useful energy. Batteries were already overcharged and the voltage regulators snapped on and off like a crackling barrage of distant heat-guns.

Below was a high gulch of the Lunar Appenines, a pattern of dazzling glare and harsh moonshadows. Ramshackle mine-buildings of prefabricated plastic straggled out from the shrouding blackness under a pinnacled ridge. Denver eyed the forbidding terrain with hair-raising panic. He checked the speed of the racing space sled, circled once, and tried to pick out a soft spot. The ship swooped down like a falling rock, power off. Denver awaited the landing shock.

It was rough. Space was too cramped and he overshot his planned landing. The spacer set down hard beyond the cleared strip, raising spurting clouds of volcanic ash which showered his view-ports in blinding glare.

Skids shrilled on naked rock, causing painful vibrations in the cabin. Denver wrenched at controls, trying to avoid jagged tongues of broken lava protruding above the dust-floor. Sun-fire turned the disturbed dust into luminous haze blanketing ship and making vision impossible. The spacer ground to an agonized stop. Denver's landing was rough but he still lived.

He sat blankly and felt cold in the superheated cabin. It was nice and surprising to be alive. Without sustaining air the dust settled almost instantly. Haze cleared outside the ports.

Charley whined eagerly. He detached himself from the tilting control panel and sailed wildly about like a hydrophobic goldfish in a bowl of water. A succession of spitting and crackling sounds poured from him as he batted his lunatic face to the view-ports to peer outside. Pseudo-tendrils formed around his travesty of mouth, and he wrinkled his absurd face into yellow typhoons of excitement. This was fun. Let's do it again!

Denver grunted uncomfortably. He studied the staggering scene of Lunar landscape without any definite hope. Something blazing from the peak of the largest mine-structure caught his eye. With a snort of bitter disgust he identified the dazzle.

Distress signals in Interplanetary Code! That should be very helpful under the poisonous circumstances. He swore again, numbly, but with deep sincerity.

Charley danced and flicked around the cabin like a free electron with a careless disregard for traffic regulations and public safety. It was wordless effort to express his eagerness to go outside and explore with Denver.

In spite of himself, Tod Denver grinned at the display.

"Not this time, Charley. You wait in the ship while I take a quick look around. From the appearance of things, I'll run into trouble enough without help from you."

The moondog drooped from disappointment. With Charley, any emotion always reached the ultimate absurdity. He was a flowing, flexible phantom of translucent color and radiance. But now the colors faded like gaudy rags in caustic solution. Charley whined as Denver went through the grotesque ritual of donning space helmet and zipping up his glass cloth and metal foil suiting before he dared venture outside. Charley even tried to help by pouring himself through the stale air to hold open the locker where the tool-belts and holstered heat guns were kept.

Space suiting bulged with internal pressure as Denver slid through the airlock and left the ship behind. Walking carefully against the treachery of moonweak gravity, he made cautious way up the slope toward the clustered buildings. Footing was bad, with the feeling of treading upon brittle, glassy surfaces and breaking through to bury his weighted shoes in inches of soft ash. A small detour was necessary to avoid upthrusting pinnacles of lavarock. In the shadow of these outcroppings he paused to let his eyes adjust to the brilliance of sunlight.

A thin pencil-beam of light stabbed outward from behind the nearer building. Close at hand, one of the lava-needles vanished in soundless display of mushrooming explosion. Sharp, acrid heat penetrated even the insulating layers of suit. A pressure-wave of expanding gas staggered him before it dissipated.

Denver flung himself instinctively behind the sheltering rocks. Prone, he inched forward to peer cautiously through a V-cleft between two jagged spires. Heat-blaster in hand, he waited events.

Again the beam licked out. The huddle of lava-pinnacles became a core of flaming destruction. Half-molten rock showered Denver's precarious refuge. He ducked, unhurt, then thrust head and gun-arm above the barricade.

wo dark figures, running awkwardly, detached themselves from the huddled bulk of buildings. Like leaping, fantastic shadows, they scampered toward the mounds of deep shadow beneath the ridge. The route took them away from Denver, making aim difficult. He fired twice, hurriedly. Missed. But near misses because he had not focused for such range.

By the time he could reset the weapon, the scurrying figures had disappeared into the screening puddles of shadow. Denver tried to distinguish them against the blackness, but it lay in solid, covering mass at the base of a titanic ridge. Faintly he could see a ghostly outline, much too large for men. It might be a ship, but it would have to be large enough for a space-yacht. No stinking two-man sled like his spacer. And he could not be sure in that eerie blankness if it even were a ship.

Besides, the range was too great. Uncertainty vanished as a circle of light showed briefly. An airlock door opened and closed swiftly. Denver stood clear of the rocks and wondered if he should risk anything further. Pursuit was useless with such arms as he carried. No question of courage was involved. A man is not required to play quixotic fool under such circumstances. And there might not be time to return to his spacer for a long-range heat gun. If he tried to reach the strange ship, its occupants could smoke him down before he covered half the distance. If he continued toward the buildings, they might return and stalk him. They would, he knew, if they guessed he was alone.

Decision was spared him. Rockets thundered. The ridge lighted up as with magnesium flares. A big ship moved out of the banked shadows, accelerating swiftly. It was a space-yacht, black-hulled, and showed no insignia. It was fast, incredibly fast. He wasted one blaster charge after it, but missed focus by yards. He ducked out of sight among the rocks as the ship dipped to skim low overhead. Then it was gone, circling in stiff, steep spiral until it lost itself to sight in distant gorges.

"Close!" Denver murmured. "Too close. And now what?"

He quickly recharged the blaster. A series of sprawling leaps ate up the remaining distance to the mine's living quarters. One whole side, where airlock doors had been, was now a gaping, ragged hole. A haze of nearly invisible frost crystals still descended in slow showers. It was bitterly cold on the sharp, opaque edge of mountain-shadow. Thermal adjustors in his suiting stopped their irregular humming. Automatic units combined chemicals and began to operate against the biting cold. With a premonition of ugly dread, Denver clambered into the ruined building.

Inside was airless, heatless cell, totally dark. Denver's gloved hand sought a radilume-switch. Light blinked on as he fumbled the button.

Death sat at a metal-topped table. Death wore the guise of a tall, gaunt, leathery man, no longer young. It was no pretty sight, though not too unfamiliar a sight on Luna.

The man had been writing. Frozen fingers still clutched a cylinder pen, and the nub adhered to the paper as the flow of ink had stiffened. From nose, ears and mouth, streams of blood had congealed into fat, crimson icicles. Rimes of ruby crystals ringed pressure-bulged eyes. He was complete, perfect, a tableau of cold, airless death.

The paper was a claim record, registered in the name of Laird Martin, Earthman. An attached photograph matched what could be seen of face behind its mask of frozen blood. Across the foot of the sheet was a hurried scrawl:

The pen had stopped writing half-through the word. Death had intervened hideously. Imagination could picture the scene as that airlock wall disappeared in blinding, soundless flash. Or perhaps there had been sound in the pressured atmosphere. His own arrival may have frightened off the claim jumpers, but too late to help the victim, who sat so straight and hideous in the airless tomb.

There was nothing to do. Airless cold would embalm the body until some bored official could come out from Crystal City to investigate the murder and pick up the hideous pieces. But if the killers returned Denver made sure that nothing remained to guide them in their search for the secret mine worked long-ago by forgotten Martians. It was Laird Martin's discovery and his dying legacy to a child on distant Earth.

Denver picked up the document and wadded it clumsily into a fold-pocket of his spacesuit. It might help the police locate the heir. In Martin's billfold was the child's picture, no more.

Denver retraced his steps to the frosty airlock valve of his ship. Inside the cabin, Charley greeted his master's return with extravagant caperings which wasted millions of electron volts.

"Nobody home, Charley," Denver told the purring moondog, "but we've picked up a nasty errand to run."

It was a bad habit, he reflected; talking to a moondog like that, but he had picked up the habit from sheer loneliness of his prospecting among the haunted desolations of the Moon. Even talking to Charley was better than going nuts, he thought, and there was not too much danger of smart answers.

He worked quickly, repairing the inadvertent damage Charley's pique had caused. It took ten full minutes, and the heat-deadline was too close for comfort. He finished and breathed more freely as temperatures began to drop. He peeled off the helmet and unzipped the suit which was reaching the thermal levels of a live-steam bath.

He ran tape through the charger to impregnate electronic setting that would guide the ship on its course to Crystal City. "We were on our way, there, anyhow," he mused. "I hope they've improved the jail. It could stand air-conditioning."