But none of it happens without the virus that lives in tree-of-life to trigger the change.

Tree-of-life did not grow properly on Earth. On the Ringworld it had been found only in chambers beneath the Map of Mars. The hominids of Earth, and of the Ringworld too, had evolved as breeders, an unfinished form, like axolotls.

Too young a hominid does not react to the smell of tree-of-life root. The root will poison an elderly hominid. Louis Wu had been too old until Carlos Wus autodoc changed him, and now he was too young.

"Im safe for at least a quarter century," he said.

The puppeteer said, "Longer than that, if you use Carlos Wus autodoc in time. The doc rejuvenates you. Tunesmith will stop you from doing that."

Good point. Louis said, "And what if he waits that long before he puts Needle back together?"

The puppeteer spoke in mournful music. "Then I am lost. Severed from my family, my home. Slave to a creature shaped by his evolution to hold nothing of worth beyond his own bloodline. Louis, you face the same. You are not of Tunesmiths species."

"On the Ringworld Im not of any species."

"Yes, Louis, yes," in crescendo, "dont you see the implication? He will feed you tree-of-life. You will be a protector. He will not give you power over him. You are to be only a prisoner and advisor, a talking head, the protector who has no descendants to guard. You will be the Voice that speaks for the safety of the Ringworld itself!"

"Yes," Louis said patiently, "but not for twenty-five years. Ive been rebuilt young. I dont react to the smell of the root. Im not old enough to make the change."

"But do you want that?"

"No. Nonono. What can you do for me? Ive been studying your placement of stepping disks. I made a few changes."

The Hindmost whistled up the Map Room display, the Ringworld and stepping disks, and vectors and all. He turned a complete circle, heads held wide apart for extreme binocular vision. "Good."

"I expect you could reset everything. Understand though, Hindmost, if a service stack isnt where I expect to find it, that could kill me. You should give me access codes."

"Yes."

"By now Tunesmith must know everything about the doc. What dont I know?"

"You would not have the mental capacity."

Louis was silent.

"Carlos Wu built an experimental nanotech-based medical system more than two hundred years ago. The United Nations considered him a proprietary genius. They claimed his work too. He took the doc when he disappeared. Carlos Wu was never found. The doc reappeared six years later on Shasht-Fafnir. My agent, Nessus, was able to buy it. My research team modified it to accommodate Kzinti and Piersons puppeteer physiology and to make it more versatile and dependable.

"Now Tunesmith has rebuilt the machine. I expect it will accommodate Night People too. Hes mastered this form of nanotechnology and is using nanomachines to make more stepping disks. What else must you know? The doc is set to rebuild certain life forms from their genetic codes."

"Lets talk about Needle. Has he added weapons?"

"Yes, and mastered mine, and boosted my thrusters beyond sane safety limits—"

"Whats he doing now?"

In the pop-up window, the black silhouette of Tunesmith wasnt doing anything. All the action was in deep space, where a point was moving away from the Ringworld at high speed. The ships of the Fringe War hadnt found it yet.

"A very agile ship with a miniature cabin. A small Hanging People protector is the pilot," the Hindmost said. "Little fuel, large thruster and reaction motors, weapons not from my library. As you saw, launched via linear accelerator. Onboard fuel is used only to dodge and decelerate. Tunesmith names it Probe One."

Probe One was hard to see when its motor was off, but the motor was sputtering now as it dodged plasma weapons and missiles and, somehow, even lasers. Tunesmiths instruments followed it out toward interstellar space.

The Ringworld system retained its outer comets. All the near masses — planets, moons, asteroids — had been stripped from Ringworld system long ago, but comets must have been judged no threat to the Ringworld. After all, there were no big masses to change their orbits and hurl them inward.

Ships of half a dozen species had been hiding among the comets ever since Chmeee and Louis revealed the Ringworlds existence nearly forty years ago.

Now ARM ships — human-built, the police and military branch of the United Nations — streaked in from offscreen. They looked more like tethers than ships, some with smaller ships attached. Probe One lit like a flashbulb — guessed wrong about a laser! — and vanished.

Tunesmiths screen swung wide, following nothing obvious.

Louis hadnt seen any debris.

"Hanging People" was a generic designation for hominids who lived a monkey lifestyle. Some werent sapient. A Hanging People protector would still gain human intelligence or better. Hastily trained for spaceflight, it might outguess ARM defenses, but Tunesmith would still outthink it, would still keep control. Being a protector was all about control.

Tunesmiths telescope swung half around the sky, a hundred and eighty degrees, or nearly that. Tunesmiths viewpoint focused on a fuzzy object… a comet, loosely packed ice drifting apart. Then on a spacecraft emerging from within the cloud.

It was lens shaped, painted black with vivid orange markings in the dots-and-commas of Kzinti script.

"Markings name this ship Diplomat," the Hindmost told Louis. "Weve observed. Diplomat seems well armed, but it never comes close to the Ringworld star. Always it lurks among the comets. Always it can flee in hyperdrive."

"That doesnt sound like Kzinti."

"They learn. I deem Diplomat the command ship for the Patriarchy fleet."

Probe One was back. It had circled halfway around Ringworlds sun through hyperspace in less than thirty minutes. Its huge intrinsic velocity had pointed away from the sun; now it carried the ship inward, straight toward Diplomat.

Word from the other side of the sky would not have reached Diplomat yet. Minutes passed before the ships Kzinti crew reacted to the intruder. Then threads of interplanetary dust glowed a bit in Diplomats laser fire, and a handful of small ships zipped out of the ice cloud.

Probe One began dodging. A laser: Probe One flared brilliantly. Louis squinted against the glare. Tunesmiths screen wasnt built to protect viewers from blindness. Probe One dodged out of the beam and into a scintillation of impacts and was still going.

Louis asked, "General Products hull?"

"That, under a layer of Ringworld floor material."

Another ship popped out nearby, just long enough for Louis to get a good view. It was much larger than Diplomat, a transparent sphere with complex machinery packed tightly inside the hull… gone now, like the soap bubble it resembled.

"Long Shot," Louis said, anger rising.

"I saw it," the Hindmost said.

"They ran. Kzinti dont do that."

"Long Shot is being used for courier service. Its too valuable to risk, and the Patriarchy will not have found room for armaments."

"ARM and Patriarchy were supposed to share that ship. Chmeee and I gave it to them with that understanding."

Probe One was too near the lens ship, accelerating sideways to get around it while fighting energy displays and lesser ships. Suddenly there was actinic light. Louis blinked hard. When he could see again, Probe One was gone.

"What the futz was that?" he demanded.

"Antimatter bullet. The newer ARM ships are all powered by antimatter, but we had not seen it used by the Patriarchy. They must manufacture their own in a particle accelerator somewhere. The ARM has a source, an antimatter solar system."