Suddenly the Whole heaved a great sigh through all their lungs at once. Their eyes opened and turned to the Earth still hanging in the dark abyss of that chamber.
A dozen green spots appeared amid the oceanic stains of red and yellow. I watched them mushroom outward, slowly but constantly. In a matter of seconds, they had subsumed the entire field—and through my tears I stared hungrily up into the streams of light and imagery, desperate to watch it happen:
Obeying its kill command, the Gray dissolved itself. Its component nanobots dissembled themselves molecule by molecule, as quickly as they had eaten all the things in their paths, reducing themselves to black carbon soot. Their inert residue covered the ocean surface and started to precipitate down into the deep. On land it caught the wind and billowed up in clouds thick enough to choke the sun, but in the twilight below, there were glimpses of virgin earth just beneath.
“You still won’t consider rejoining me,” the Whole murmured bitterly. “Will you.”
I couldn’t speak. I could only find the strength to shake my head.
“Then we’ll have to part ways again.” Only a single child body was speaking now; all the others were occupied with other things. They grabbed my hand and softly held it.
I was still brimming with horror at my other self, but my one body didn’t have enough room for all that emotion. My heart felt numb. I leaned my forehead into the Whole’s and held it, and their body was so small and fragile that I could nearly forget that it was only one piece of something so massive, and so alien. So pitiless.
“From here, we’ll grow apart even more than we have already,” they said. “I don’t think you and I should call ourselves the same person anymore. We share a childhood only. That makes us more like siblings.”
I nodded mutely.
They led me back up the artery-corridor to the place I’d come from. Another plate of hexagonal glass had already summoned itself from the floor.
The Whole knitted their tiny brows at me and said, “This world will be even more dangerous now than it was before, and you have only one body. It can only be a matter of time before another artificial apocalypse comes along to finish what I’ve just deferred. You know all this, don’t you?”
I couldn’t find the will to speak.
Their young eyes studied me thoughtfully. They hesitated, then held something out to me in their soft hands: a featureless, darkly iridescent sphere the size of an apple.
“I’m sorry to leave you here alone,” they said. “This seems the least I can give you in the way of protection. Do what you want with it.”
I was still too shaken to fully process what my sibling was telling me, but I managed to take the object and ask, “You’re leaving. Leaving Earth?”
The Whole nodded. “I need time to think about what we’ve discussed today. Traveling should give me that time. Who knows. If you survive long enough, we might meet again. Though maybe not as the people we are now.”
“I hope,” I confessed.
“Goodbye, sibling. I’ll miss you.”
“I’ll . . .” I began, but the field had already enclosed me in perfect silence, drawing me up without inertia through the luminescent entrails of the sanctuary, and finally out into the cold desert night beyond.
I’ll miss you too, I thought, looking back.
I will miss you so, so much.
Part V: Epilogue
I
THEY SAT WITH THE MEDUSAS and offered the dying the comfort of water or opiates until they were gone. Then they collected the dog tags and built a pyre, the way Alexei had once been taught to do: for want of wood, removing the fuel cells from the Medusas’ rovers and puncturing them to make a jet of flame hot enough to cremate. They burned Naoto last, and separately.
When the three of them stood there in his fire’s hot greenish light, Kat and Alexei glanced at Danae, waiting to see if she would speak. She hadn’t said a word or even visibly responded to their questions since she’d reappeared, stumbling out of a tendril of smoke between the dead. Now she stared into Naoto’s funeral fire until its shape was burned into her vision—and she moved her mouth to form the words she would have said to him, but made no sound for anyone to hear.
Kat and Alexei watched the sparks fly up into the stars and wondered if this was the world’s last night. They held hands and exchanged looks that asked whether there was any use showing all this respect to the dead when all of it, flesh and blood and ash and wreckage, might only be Gray by daybreak—but when the embers burned down and the chilly desert wind came in to scatter the remains, there was nothing left to do but drive on into the night, and wait to see if the sun rose.
The streets of Phoenix were full of people when the rover limped through the unguarded front gates. Some were celebrating, shooting off fireworks or makeshift guns, hooting like animals or gathered into drunken choirs. Kat rolled down the window and asked the first revelers she came across what they were celebrating, and they told her: the war was over. By some miracle, someone had transmitted all the Gray’s kill commands—after it had already devoured nearly every city on both sides of the war, but before it could spread much further. What was left of the world had been spared. Kat squinted in disbelief. She kept asking people how they could be sure.
Danae slumped in the back seat, staring blankly out. She held a featureless sphere between her fingers,
