Chameleon was Dread. Which didn�t surprise Mallory, since Chameleon was always Dread for him. Under the circumstances, he thought, perhaps it was best, today, that Chameleon was Dread.

�We�ll never make it,� said Dread. �It�s too far. We don�t have enough air. We are going to die.�

Mallory laughed, the sound going flat inside the helmet of his spacesuit. Behind him, Lunar Defense Complex 3 was a blackened pit in Mare Nubium; a crater so new the dust was still settling, black and scorched, all around the hole, giving the overhead stars a misty shimmer that covered Mallory�s suit with black snow whenever he stood still long enough.

And ahead, somewhere ahead, was his only chance for survival.

�Ah, my dear Dread! What adventure, what challenge. This is what living is all about. This is what legends are made of.�

Dread groaned.

Mallory replayed the last battle in his mind. The Cascadian invasion fleet was broken, defeated. The last great cruiser swept low over the Moon, its alien pilot desperate or dead, its winged mass turning, dipping. LDC-3 fired its main batteries in desperation. A hit. Another. The cruiser, sliced almost in half, disappeared over the horizon. But not before that great bird gave birth to one tiny, red egg.

The egg was a fission device.

LDC-3 was its target.

Now, Mallory was alone. Alone on all the Moon to celebrate humanity�s final victory, a victory bought with blood, but a victory nonetheless.

�I hate people who are happy all the time,� said Dread. �I always wonder what they�re trying to hide.�

Mallory smiled at this, but he didn�t answer the voice in his head. Instead, he activated his suit�s locator, using precious battery life to get an accurate fix on his destination. There. Air Station Omega. Life. There, just there. Just�

�Thirty-seven kilometers? You must be joking, Mallory.�

�We can make it,� he told Dread. �We�ll travel south first, into the substation grid. The air caches will lead us to the station. There�s all the air we need there, and we can contact Earth.�

He glanced up at the blue orb as he spoke. Earth, a sapphire on black velvet. So close he could almost reach out and touch it.

�Maybe some Cascadian weapons got through,� said Dread. �Maybe there�s no one left on Earth to contact.�

Mallory laughed. He tried to associate the disembodied voice with the tiny pellet he knew nestled at the base of his brain. As usual, he failed. Chameleon implants, he thought. Artificial intelligence. What a pain in the brain. Just once I�d like to be alone with my thoughts. �If that were true, Dread, which it isn�t, then what productive strategy would you recommend?�

Dread�s voice was a cold tickle along the aural receptors of Mallory�s brain, as cold as the airless world around them. �Save yourself the burden of hope,� he said, �the pain of lingering death. Open your helmet now.�

Mallory shivered. �We�re wasting time,� he said, and he called up the substation grid. Green lines splashed across his visor, virtual vectors that moved as he turned through a complete circle. The nearest substation was less than a kilometer away.

He started walking.

Chameleon was Dread, and Dread didn�t take well to having his suggestions ignored. Dread sulked all the way to the substation. Mallory�s senses fed on themselves as he moved in bounding leaps along the green line. The lunar soil shifted each time his boots dug in for the next leap, its consistency that of powdered chalk. His breath rasped inside the helmet, in time to the beating pulse in his ears: thud thud rasp, thud thud rasp. He�d set his oxygen mix at MAX-CONSERVE, and the tang of impoverished air burned his nostrils and made his mouth pucker, like biting into a lemon.

He laughed. He was alive! Think of all the poor slobs who never see beyond the walls of their safe, drab lives. Think of their arteries clogged with sediment and their minds set in thickening molasses and their hopes and dreams all smothered by monotony and routine. I could never live like that, thought Mallory. Would never want to. I am exactly where I want to be, doing exactly what I want to do, being exactly who I want to be.

�Our oxygen supply is half depleted,� said Dread, a few minutes later. �Or would an optimist say half full?�

Mallory grinned. �Don�t be sarcastic, Dread. You�re right: the tank�s half empty. But guess what? We�ll be filling it momentarily.�

Dread sighed, disappointed no doubt. Two minutes later they reached the substation. It was nothing but a white and black checkered cylinder, set half below the surface and half above, about the size of a man. Mallory jacked in, turned two safety knobs on the cylinder, two more on his suit. A faint hiss confirmed his tank was being filled.

He waited.

�So, Dread, we�re still alive.� He�d taken to teasing the AI implant lately, which was probably cruel, and almost certainly a waste of breath, but he could hardly resist.

�A temporary condition,� answered Dread.

�Of course! Death is inevitable one day. And when it comes, I think I shall embrace it, eager to learn what awaits me on the other side.�

�Nothing awaits you but oblivion, Mallory. You die, your life�s work is forgotten, and you cease to exist. Anything else is a delusion.�

Mallory nodded. It was an argument they�d had many times. �I�ll be happy however it turns out,� he said.

�Probably. That�s the depressing part.�

The tank was full. Mallory closed both sets of safety valves and jacked out. The green vector on his visor beckoned him onward. He moved out.

The next substation was empty. A micrometeorite impact and a slow leak, it looked like. A frosting of ice on the surrounding rocks confirmed the hypothesis.

�We�re finished,� observed Dread.

Mallory shook his head. �Not at all. We�ve got more than enough air to make the next substation. Then only a little farther to Omega.� He pictured the air station vividly, its life module small by some standards, spacious alter the long hours in the suit. Plenty of air there, plenty of food. Maybe other survivors had made it in ahead of him. Maybe they�d already contacted Earth and gotten a rescue ship dispatched.

Then home. Returning as a hero. The lone survivor of LDC-3, or one of the proud few. Stories to impress the ladies, their eyes big and round in wonder. Then, later, the children, the grandchildren. �What did you do in the war, Grandpa?�

�Oh, not much. Just saved the Earth single-handedly is all.�

Mallory stopped, giving his legs and back a moment to rest while he took in the stark beauty of the lunar landscape. His coworkers at the defense complex had often complained of �the grays,� a state of pseudodepression they claimed was induced by the dreariness of their surroundings. To Mallory, the great sweeping plains and the angular mountains and the sharp divisions between light and shadow had always combined to form new and surprising depths of alien beauty.

�Mallory,� asked Dread, �what do you see when you look out there?�

They were halfway between substations now. Mallory thought if he could remove his helmet, the lunar night would be silent and crisp, like the predawn hours of a winter morning back home in Juneau.

�Alaska,� he said. �I see Alaska. That�s my home, you know. Parts of it are very much like this: rugged, alien, inhospitable. Not a place meant for human beings. But we go where we weren�t meant to, don�t we? And we thrive there. It�s part of our nature. Part of what makes us great.�

Dread made a noncommittal grunt. �Alaska,� he said. �That figures. It supports my theory, too.�

�What theory�s that, Dread?�

�My theory that you�d lack any sense of reality at all if not for me. Not that you have much of one now.� Mallory chuckled. �You know something, my friend? They made a mistake when they named you Chameleon. It should have been Antithesis.�

�Perhaps. My synapses are fluidic, designed to change as the complement of my host. I give you balance. All of my kind give all of your kind balance. Even less extreme personalities than yours lack balance. An isolated mind is an unhealthy mind.�

�I don�t know, Dread. Homo Sapiens did fine without you for many thousands of years.�

�You survived. Somehow. You did not �do fine.� Before the Joining, all humans were, to one extent or another, insane.�

�Insane enough to create you. Maybe you�re right.�

Dread had no answer for that. He went back to sulking.

They reached the next substation, and it was intact. Mallory dozed off while the tank was filling. He dreamed. In his dream, he saw the gutted Cascadian ship sliding over the lunar horizon. He waited for the shock of impact, but instead he found himself awash in a sea of screaming, panicked voices. The scent of fear was a real thing one had to experience to fully appreciate.

Bodies pressing together, fleeing for airlocks or cover or each other. Desperate cries. Hopeless sobs. Mallory calmly donned a spacesuit, entered the rover bay, and powered up a rover. Voices screamed at him over the radio link. �You�re crazy!� �You�ll never make it in the open!� �You�re safer inside the complex!�

Mallory drove. Overhead, the red egg of death was spiraling in toward the base. There. That crater. Mallory rammed the throttle forward, disengaged the inhibitors when they sensed the uneven terrain ahead. The rover hit the crater rim, vaulted into empty space, then slowly, so slowly, dropped into the crater itself.

Two violent quakes followed. One was the rover crashing into lunar rock on the crater floor, falling to pieces around him. The other was LDC-3 exploding. Searing light, the light of death, flashed overhead. The crater wall, however, shielded Mallory from the worst of it.

It was hopeless, impossible. Only an optimist could have survived.

�Mallory?�

Mallory opened his eyes. He just wanted to sleep. How long had it been now? Traveling in a spacesuit was tiring work. He�d had nothing to eat or drink in hours.

�Tank�s full,� he said. �Time for the final push. Ready, Dread?�

Dread hesitated. He was probably searching for gloom and doom again, thought Mallory. Then the AI said, �As ready as I�ll ever be.�

Mallory beamed. �Good old Dread! That�s the spirit! We�re home free now. Just imagine the azure pools of the air station, the delicacies we�ll be served by the nubile nymphs whose only pleasure is to welcome the weary traveler with song and wine and companionship.�

�Come off it, Mallory. There�s nothing like that in the station.�

�Well, of course there isn�t. It never hurts to dream. A hot meal and a bed will feel like paradise enough.�

�You make me sick.�

�Then turn yourself off.�

Dread made no further comment as Mallory covered the final distance, humming, then singing as he felt his excitement and energy soar. He�d done it. He�d done the impossible. Again. Sometimes his brilliance astonished even him.

One kilometer now. A ridge blocked his path. It was part of a ray extending from a big crater several clicks to the north and disappearing over the opposite horizon, separating him from the air station, eclipsing it from view. He could search for a fissure or gap in the ridge, but that would take time, and he didn�t have time. So he started climbing.

It was slow, exhausting work, even in the Moon�s feeble gravity. Sweat fogged his visor. Telltales reported oxygen usage way up. The tank was three-quarters depleted. And then success. He got his hands on the top of the ridge, braced himself, pulled himself up. When he�d gotten his feet under him, he looked down.

At a mass of charred, twisted metal.

�No,� he whispered.

But it was true. It was all there, the whole story, written in debris across the airless surface of the Moon. The Cascadian ship had broken into two pieces before impact. One half, the lighter, had sailed on for half a kilometer before gouging a long furrow in the lunar soil and burying itself at the furrow�s terminus. The second, heavier fragment had dropped almost straight down out of the sky.

And onto Air Station Omega.

Mallory found himself on the ground, realized that his knees had buckled. He felt cheated, empty, angry and numb all at the same time. That was it, then. All for nothing. The station was gone. His suit air was almost depleted�not even enough to make it back to the last substation. He was going to die. He was really, really going to die.

Reality shifted. How childish he had been! The Universe was a dark, hungry place, his life the hot flicker of a dying candle. All his life he�d spun a web of lies to conceal this reality from his own innocent eyes. Now the web had come unraveled, and he saw it all as it was, as it really was, and he wept more at his own foolishness than at the dark wings of death he sensed circling above him.

�You were right, Dread,� he sobbed. �You were right all along. My God, what a waste. What a pathetic waste.�

Silence.

�And you know the worst part, Dread? We never even found out where they came from. They know where we are all right, but we can only live in fear of the night now, always wondering if they might return.�

Silence.

�Dread? Talk to me, Dread. I need you now. I need to know that at least I still have you.�

Silence.

Damn, thought Mallory. So Dread has won and now he�s gloating, won�t even talk to me. Fine. Maybe I�ll open my helmet and end it all right now. Yes, that is the easiest way. I can�t stand living like this.

Mallory raised his hands toward his suit�s neck seals. A voice stopped him.

�No,� said Dread, �don�t. There�s always hope.�

Mallory froze. Had he already died? Or just gone crazy? �What did you say?� he whispered.

Dread�s voice was gentle, reassuring. �We still have thirty minutes of air. A lot can happen in thirty minutes.�

�I don�t believe this,� said Mallory. �Why are you�� And then it came to him, and he laughed. �I get it. I get it. Chameleon. Antithesis. Now you�re an optimist. Now that I�ve given up all hope.�

�My synapses are fluidic. I adapt to your changing behavioral and thought patterns, endeavoring to complement your personality, to compensate for your deficiencies. I��

�You and your fluidic synapses! Leave me alone! Do you hear? We�re dead! Dead, dead, dead. So what�s the point?�

�Go down to the wreckage,� Chameleon, who was no longer Dread, urged. �There may be oxygen canisters that were not consumed in the explosion.�

Tired, so tired. But Mallory got up, feeling pain in every muscle and joint, and climbed down the front of the ridge to the remains of Air Station Omega. At least it would pass the time until�

Desolation. Lovely desolation. It was appealing somehow, like dark comedy or mood art. Mallory moved among the wreckage, taking in the ghastly beauty of destruction, the broken symmetry of a girder rising out of a shattered sublevel, a halfmelted control panel dangling from an airlock archway left almost intact, an alien jumble of octagons and rhomboids etched with strange, indecipherable writings.

I am not the observer of this piece, Mallory thought. I am a part of it. He checked telltales. Or I will be, in twelve minutes.

�So much for your theory,� he told Chameleon. �No air cylinders here. But it is a fitting graveyard. Just one more tombstone to erect.�

�Stop feeling sorry for yourself, Mallory. Turn to the left. A little more. There. What�s that?�

Sixty or seventy meters from the edge of the destruction, there was an object. �I don�t recognize it,� Mallory said, not really trying.

�Exactly,� said Chameleon. �Walk us over toward it.�

Mallory started to protest. What was he, a puppet on a string to this AI implant? But then he thought: what the hell? It would all be over soon anyway. He thought of his former self, so idealistic, so eager for life. Like a child. A child who never grew up. Just now, he felt no curiosity at all.

�Just like I thought,� Chameleon said when they were halfway to the object. �Look at those markings. It�s Cascadian.�

�So what?� groaned Mallory. �Another piece of debris.� But his eyes studied its peculiar, spherical shape as he drew nearer. It was like a giant egg, white as snow, with a transparent slice through one side.

Light streamed out through the slice.

�Mallory, I think��

His heart was pounding now. Because he saw what the thing was, he saw what was inside it. �My God,� he whispered. �So that�s what they look like.�

The Cascadian appeared unconscious. It was twice the size of a human, with a sort of jointed torso and sinewy arms that looked more like leaf-covered vines than flesh and blood. It had a small, tube-shaped head from which dangled three sets of purplish organs resembling bunches of grapes. Its entire body was bathed in a white light so brilliant it was almost blinding, even through Mallory�s tinted visor.

�Is it� alive?� Chameleon asked.

Mesmerized, Mallory just stared. Then a red indicator flashed inside his helmet, signaling that his tank was empty and the five-minute emergency air supply had engaged.

Great, he thought. I�m the first human to see the face of my enemy, and now I get to die. Just great.

�Mallory, I have an idea. Maybe it breathes oxygen.�

Mallory snorted. �And maybe it breathes chlorine. What are you proposing?�

�See those octagonal plates beside the transparent slice?�

Mallory nodded.

�They look like controls, don�t they?�

�You mean� get into that thing with him? You must be out of my mind.�

Chameleon ignored the joke. �Quick, Mallory. Time is short. If it breathes air with oxygen in it, you might just survive until rescue arrives.�

It occurred to Mallory that Chameleon would survive anyway, its silicon neurons impervious to vacuum or oxygen depletion. This made Mallory very angry.

�All right, damn you.�

He began pressing the octagonal plates. They lit up when he touched them, but nothing else happened. He realized it must be some kind of combination. He tried pushing several plates at once. He tried pushing them in different sequences. His air was running out. Then he got lucky.

The transparent slice opened out, and Mallory saw that there were two of them, one inside the other, a kind of airlock. He stepped in, and the floorplate lit up, and the outer slice closed.

The inner one opened.

I can�t believe I�m here, thought Mallory. The egg was big enough for him and the Cascadian�barely. The creature seemed to be in some kind of hibernation. Or dead. The white light he had observed earlier was radiating down from panels in the ceiling, and he could see wires curling from the panels to a silvery globe embedded in the wall above the Cascadian�s head. Some kind of generator, he thought. Photosynthesis. But that would mean�

�Take off your helmet,� said Chameleon.

Mallory felt his heart begin to race. It was against every safety regulation. It was insane. He didn�t have time to test this air. There was no telling what it was composed of, what the pressure was, what sort of alien microbes were present.

He felt suddenly drowsy, so very, very drowsy.

�Mallory!� a distant voice called. �Your emergency tank�s empty. Open your helmet!�

Sleep. I just want to sleep.

�Mallory!�

Chameleon. Good old Chameleon. You will live, my silicon friend. You are my better half, and you will live.

Then, somehow, his helmet was off, and his ears were ringing, and his nostrils burned and his eyes watered under that bright, bright light, but his lungs expanded� contracted� expanded.

His head began to clear.

�You did it,� said Chameleon. �I knew you would. I just knew it.�

�Oxygen?� Mallory asked.

�Look.�

Mallory shielded his eyes from the light and looked at the Cascadian. The purple grapes on the thing�s head were changing color now, turning red, then blue. Its �leaves� were changing, too, going from yellow to green. All the while this was happening, Mallory became aware that his breath was coming easier.

�Don�t you see?� asked Chameleon. �It�s a C0₂ breather. It�s taking the air you exhale and absorbing the carbon dioxide and giving off oxygen.�

Mallory blinked. �But is that possible? No single plant could��

�This isn�t an Earth species, Mallory. From the light input it�s absorbing, I�d estimate its metabolic rate at something comparable to your own. Once you reach equilibrium, the two of you could sustain each other indefinitely.�

Great, thought Mallory. Just great. My enemy�humanity�s enemy. The thing that did this to us, that almost did so much more. Red rage swelled inside his chest. Kill the invader! Kill!

He looked the alien over. Not much, up close. Thin, weak, unconscious and vulnerable. It looked like it might be injured: some of the �vines� on its lower torso had been torn out, detached, and were withering. It would be so easy to finish the job.

�Don�t be a fool, Mallory. He�s recycling your air. Kill him, and you die with him.�

Mallory closed his eyes against the rage, the race-hatred, the instinct for revenge. Chameleon was right. Kill it, and he would be killing himself. But� did he care enough about himself not to?

�You made it, Mallory. You were right all along. You�re safe now. As long as our friend here keeps breathing, we should be able to survive for days. And this will be the first place the rescuers come when they find no survivors at LDC-3.�

Noise. Noise in his head. Damn the noise. Damn it all, anyway. Who cares? Mallory shook his head. Who cares if I live or die? What does it matter? It�s only me.

Then he looked up again, stared at the Cascadian. Arrogant butchers! They�d come without warning, bold and brutal, their aim the total conquest of Earthspace. Only the Lunar Defense Complexes had stopped them. And at such a cost�

Mallory felt the anger maturing inside him. They�d failed� this time. But what if they tried again? He squinted. The light in here could be the finish of his retinas, but it gave him an idea. The Cascadian might require light similar to that of its native sun. Light could be analyzed, broken down into a spectrum, compared to the spectra of various nearby stars.

We could find their home world, Mallory thought excitedly. At last, we could learn their point of origin. Sure, it was a long shot. Humans used incandescent light sources whose spectra were closer to a red dwarfs than to Sol�s. But then, human beings didn�t live by photosynthesis. And even if it was a long shot, it was better than nothing. It was a beginning.

Mallory felt the idea changing him. Suddenly he realized he had to survive, no matter the cost. He had to be there, tomorrow and the day after, to help in what small way he could.

�All right, Chameleon. We�ll play it your way. I�ll be damned if I�ll die out here, like this, after what I�ve been through. Hell, the worst part�s behind us, right? We haven�t come this far to lose it all now.�

Chameleon was silent.

�Chameleon? I said�� And he understood. The switch. Like before. The period of silence, the gap while the change took place.

�Chameleon,� Mallory said, �listen to me very carefully. We are going to live. You�ve convinced me. And you�re still the optimist. Your fluidic synapses are trying to change, but that takes a minute or two, doesn�t it? Don�t let it happen. You�ve seen how bright the world can be, how positive thought can overcome almost any obstacle. You don�t want to go back to being Dread.�

Silence.

�And you don�t have to. Believe in yourself. You are the pinnacle of artificial intelligence. You�re a marvel. You can reprogram yourself at will. You can become the opposite of your host, the mirror image. But you don�t have to become that. You can make a choice to become more. You can become whole.�

Mallory waited, listening for that inner voice. He could be here a long time before they found him. He could go crazy if Dread returned, filling his mind with paranoid suspicions of flesh-eating plants and deadly airborne viruses. He could freak out and do something stupid. This wasn�t pessimism; it was simply reality. Something he�d learned was neither white nor black but every shade in between.

He didn�t want to die.

So he waited.

And, presently, Chameleon spoke.

�Thank you,� was what Chameleon said. �Thank you, Mallory, so very, very much.�