"We had one marvelous day when Mirrim discovered the beads under the microscope. Aivas was excited, too, for he feels certain that the beads are the genetic information of the Thread organism." She grinned as she remembered that moment of triumph. "The microscope was at sub-high for maximum magnification, so we could all see these tiny, tiny beads strung along one of those long wires I told you Thread has. Not the springs, but the wires, which are coiled ever so tightly in a volume no bigger than the tip of my finger. Aivas says these ring beads use the material of the Thread ovoid to reproduce themselves." She made a face, indicating her ignorance of how that was done. "What he wants us to find now is a bacteriophage to infect the beads and then discover just the right one that will replicate itself fast before it uses up all the Thread material. We've done something of a similar nature, you know, when we located bacteria from wounds and learned how to disimprove their symbiotic bacteriophages so that they would kill their hosts. Our ancestors could certainly do marvelous things biologically to heal people. I hope we can begin to do as well as they did. This exercise could heal our planet."
"Then why didn't they do it?" Jaxom asked. "Why are we left with the job?"
Sharra grinned smugly. "Because we have dragons to replace fuel-less shuttles, fire-lizards who can nick Thread ovoids out of space, and Aivas to tell us exactly what to do. Even if I don't always understand what we're doing or why we're doing it."
"I thought you said it was to disimprove the Thread's symbionts. Though why that's necessary with what the dragonriders are to do, I don't know."
Sharra was silent a moment, considering that. "Aivas hates Thread, inasmuch as an inanimate machine is capable of hatred. He hates what it did to his captains and Admiral Benden. He hates what it's done to us. He wants to be sure it can never menace us again. He wants to kill it in the Oort Cloud. He calls the project 'Overkill.'"
Jaxom regarded her in puzzled astonishment. "He's more vindictive than F'lar!"
Sharra sighed dejectedly. "I m not sure that we can do what he wants. It's all so very complicated. And we're so limited in our understanding. He may be the machine, but I feel like one, doing this and that without knowing why."
She was more buoyant three days later when she told Jaxom that Aivas had found the appropriate parasitic vector.
"He says that similar life-forms were found in micro-gravity conditions in the asteroid belts. It's very like the one found in the ecology of the Pluto/Charon pair in the original Earth Solar system." Sharra frowned in perplexity. "Well, that's what he says. He has named the springs 'zebedees.' And zebedees are what we will now use to make our tailored parasite, like a virus, jump from one Thread ovoid to the next... once the parasite has disimproved itself as a symbiont and became really destructive! We've got to culture it now, though."
Jaxom managed a suitably appreciative grin for her enthusiasm. "Who are we to protest an Aivas pronouncement? What next?"
"Well, he's got all the fire-lizards searching the ovoid streams for the springs. Sometimes they're embedded right on the surface of an ovoid. We've had to start up nine more cold capsules to contain the things and infect them with the zebedee-makers."
"Zebedees, the Thread fleas!" Jaxom said, teasingly.
"Well, fleas are parasites, and I could wish we were able to disimprove some of them quickly! As it is, the time we have is nowhere near long enough for the work we have to do."
She had been disgusted to discover canine fleas on Jarrol, who was incurably attached to one of the kitchen-spit animals. "Fleas!" She shook her head. "That will be my priority project, as soon as we're finished with Aivas's: to disimprove fleas."
"Whenever that'll be," Jaxom added. There were so many Aivas endeavors, at various stages of completion, that he wondered if any of them would get finished on time now that the deadline drew nearer.
"Would you and Ruth have time to get me back to the Yokohama tomorrow before you fly Fall?" Sharra asked.
Jaxom groaned. "I thought you'd be here a few days."
Sharra looked properly repentant. "I've been over everything for the Gather with Brand and the other Stewards, and all's ready for our guests. But this is an especially critical time, Jaxom..." Her eyes pleaded for his understanding.
"You'll be exhausted. You won't enjoy the Gather..." he heard himself saying, and then he pulled her into his arms, savoring the feel of her body against his, and the spicy fragrance of her hair. Gathers were always special times for them.
"Please, Jaxom?" Her lips brushed his neck.
"I'm just griping, love. I could never keep you where you didn't wish to be."
"Won't it be wonderful, when this is all over, to be just us again?" she asked. "I want a daughter, too, you know."
That earnest wish elicited a response he was glad to make.
Threadfall was uneventful, though it was not one in which the spaceships' shields had carved tunnels of Threadfree air. Then Hamian sent a message that he had a new glove for Ruth to test on an EVA. So, after Ruth had tested it and found it comfortable as well as a good shield with an easy buckle attachment to hold it in place, Jaxom reported the success to Aivas to pass on to Hamian. For a change, Jaxom and Ruth were alone on the bridge: Ruth was spread across the big window as usual, devouring his favorite view.
"Aivas, just why are you so obsessed with this zebedee project?" Jaxom asked when he had delivered his message to Hamian. "Sharra says you call it Overkill. Why isn't blowing the Red Star out of orbit sufficient?"
"You are alone?" Aivas asked.
That was an unusual question, as Aivas usually unerringly sensed additional presences.
"Yes, I'm alone. Are you going to come clean?" Jaxom asked, half joking.
"This is as good a time as any," Aivas replied, startling the young Holder.
"That doesn't sound good."
"On the contrary, it is all to the good to know what has been expected of you since this facility learned of Ruth's unusual abilities."
"His knowing when and where he is?" Jaxom asked slyly.
"Precisely. An explanation is needed."
"They usually are, with you!"
"Flippancy has always covered apprehension. Candor is required. There are three engines that must be exploded to push the Red Star out of an of hazardous to Pern. Two of those explosions have already taken place."
"What?" Jaxom sat upright in the comfortable chair and stared at the screen in front of him.
"As you are aware, records from every Weyr, Hall, and Hold were presented and analyzed. Two small entries illuminate an anomaly.
"Based on the position of the Red Star when Mankind first landed on Pern, that planet is not now in the orbit it should be tracking at this point in time. Repeated calculations were made during the First Fall by captains Keroon and Tillek. Eccentric it might be, but its current position differs from an extrapolation of those original calculations. Its path shows that it has suffered a perturbation of nine-point-three degrees off its original elliptical orbit. That is not consistent with the extrapolated position. Therefore, something has already altered its path. Substantiation occurs in two minor references found in Istan and Keroonian records in the Fourth and Eighth Passes, which were each prior to a long Interval. During each Pass, bright flashes were observed when the Red Star was at apogee in reference to Pern. Bright enough to be remembered and noted."
Stunned, Jaxom blinked, as if closing and opening his eyes would help him focus his thoughts on what Aivas was saying. "Those two craters?"
"Your perception is acute."
"My fear is also, Aivas!"
"Man is wise to fear: it sharpens the sense of self preservation."
"But what I felt when I saw the first crater was not fear. It was-it had to be-it was as if I knew it had to be there! I discounted such a ridiculous notion at the time. And you, Aivas, would not have me believe that I have been there before?"