Xenocide (Ender Wiggins Saga)

the edge of death and Ela was at the edge of exhaustion. Her team had worked through the night; Quara had helped, constantly, indefatigably reading over everything Ela's people came up with, critiquing, pointing out errors. By midmorning, they had a plan for a truncated virus that should work. All of the language capability was gone, which meant the new viruses wouldn't be able to communicate with each other. All the analytical ability was gone as well, as near as they could tell. But safely in place were all the parts of the virus that supported bodily functions in the native species of Lusitania. As near as they could possibly tell without having a working sample of the virus, the new design was exactly what was needed-- a descolada that was completely functional in the life cycles of the Lusitanian species, including the pequeninos, yet completely incapable of global regulation and manipulation. They named the new virus recolada. The old one had been named for its function of tearing apart; the new one for its remaining function, holding together the species-pairs that made up the native life of Lusitania.
    Ender raised one objection-- that since the descolada must have been putting the pequeninos into a belligerent, expansive mode, the new virus might lock them into that particular condition. But Ela and Quara answered together that they had deliberately used an older version of the descolada as their model, from a time when the pequeninos were more relaxed-- more "themselves." The pequeninos working on the project had agreed to this; there was little time to consult anyone else except Human and Rooter, who also concurred.
    With the things that Quara had taught them about the workings of the descolada, Ela also had a team working on a killer bacterium that would spread quickly through the entire planet's gaialogy, finding the normal descolada in every place and every form, tearing it to bits and killing it. It would recognize the old descolada by the very elements that the new descolada would lack. Releasing the recolada and the killer bacterium at the same time should do the job.
    There was only one problem remaining-- actually making the new virus. That was Ela's direct project from midmorning on. Quara collapsed and slept. So did most of the pequeninos. But Ela struggled on, trying to use all the tools she had to break apart the virus and recombine it as she needed.
    But when Ender came late in the afternoon to tell her that it was now or never, if her virus was to save Planter, she could only break down and weep from exhaustion and frustration.
    "I can't," she said.
    "Then tell him that you've achieved it but you can't get it ready in time and--"
    "I mean it can't be done."
    "You've designed it."
    "We've planned it, we've modeled it, yes. But it can't be made . The descolada is a really vicious design. We can't build it from scratch because there are too many parts that can't hold together unless you have those very sections already working to keep rebuilding each other as they break down. And we can't do modifications of the present virus unless the descolada is at least marginally active, in which case it undoes what we're doing faster than we can do it. It was designed to police itself constantly so it can't be altered, and to be so unstable in all its parts that it's completely unmakable."
    "But they made it."
    "Yes, but I don't know how . Unlike Grego, I can't completely step outside my science on some metaphysical whim and make things up and wish them into existence. I'm stuck with the rules of nature as they are here and now, and there's no rule that will let me make it."
    "So we know where we need to go, but we can't get there from here."
    "Until last night I didn't know enough to guess whether we could design this new recolada or not, and therefore I had no way of guessing whether we could make it. I figured that if it was designable, it was makable. I was ready to make it, ready to act the moment Quara relented. All we've achieved is to know, finally, completely, that it can't be done. Quara was right. We definitely found out enough from her to enable us to kill every descolada virus on Lusitania. But we can't make the recolada that could replace it and keep Lusitanian life functioning."
    "So if we use the viricide bacterium--"
    "All the pequeninos in the world would be where Planter is now within a week or two. And all the grass and birds and vines and everything. Scorched earth. An atrocity. Quara