“I can try.”

“They put maps all over the Great Oceans. Instead of mapping Kzin and Down and Mars and Jinx, can you tell me why Pak protectors wouldn’t just exterminate the kzinti and Grogs and martians and bandersnatchi?”

“Uurrr. Why not? The Pak would not flinch at exterminating alien species, according to Brennan.”

Chmeee paced as he mulled the problem. He said, “Perhaps they expected to be followed. What if they lost a war; what if they expected the winners to come hunting them? To the Pak, a dozen burnt-out worlds within a dozen light-years of one another might indicate the presence of Pak.”

“Mmm … maybe. Now tell me why they’d build a Ringworld in the first place. How the futz did they expect to defend it?”

“I would not attempt to defend a structure so vulnerable. Perhaps we will learn. I have also wondered why Pak would come to this region of space in the first place. Coincidence?”

“No! Too far.”

“Well?”

“Oh … we can guess. Suppose a lot of Pak wanted to run as fast and as far as they could. Again, say they lost a war. Got kicked off the Pak world. Well, there was one safe route out into the galactic arms, and it was mapped. The first expedition, the one that settled Earth, got to Sol system without running into any danger they couldn’t handle. They sent back directions. So the losers followed them. Then they set up shop a good safe distance from Sol system.”

Chmeee mulled that. Presently he said, “However they came here, the Pak were intelligent and warlike xenophobes. That has implications. The weapon that vaporized half of Liar, the weapon you and Teela persisted in calling a meteor defense, was almost certainly programmed to fire on invading ships. It will fire on Hot Needle of Inquiry or the lander, given the chance. My second point is that the Hindmost must not learn who built the Ringworld.”

Louis shook his head. “They must be long gone. According to Brennan, a protector’s only motivation is to protect his descendants. They wouldn’t have let mutations develop. They’d never have let the Ringworld start sliding into the sun.”

“Louis—”

“In fact they must have been gone hundreds of thousands of years. Look at the variety of hominids we’ve found.”

“I would say millions of years. They must have departed soon after the first ship called for help, and died soon after completing the structure. How else would all of these varieties have had time to develop? But—”

“Chmeee, look: suppose they finished the Ringworld a mere half million years ago. Give the breeders a quarter of a million years to spread out, with the protectors fighting no wars because the territory’s virtually unlimited. Then let the protectors die off.”

“From what?”

“Insufficient data.”

“Accepted. Well?”

“Let the protectors die off a quarter of a million years ago. Give the breeders a tenth the time it took humans to evolve on Earth. A tenth of the time, and a lot of nice gaps in the ecology because the protectors didn’t bring anything to prey on the breeders, and a base population in the trillions.

“See? On Earth there were maybe half a million breeders when the protectors died out. On the Ringworld, three million times the room, and plenty of time to spread out before the protectors died. The mutants would have it all their own way.”

“I don’t accept that you’re right,” Chmeee said quietly. “I do feel that you’ve missed a point. Granted that the protectors are almost certainly gone. Almost certainly. What if the Hindmost learns that this was their property, their home?”

“Oops. He’d run. With or without us.”

“Officially we have not penetrated the secret of the Ringworld’s construction. Agreed?”

“Yah.”

“Are we still looking for the Repair Center? The smell of tree-of-life might be deadly to you. You are too old to become a protector.”

“I wouldn’t want to. Is there a spectroscope in the lander?”

“Yes.”

“Tree-of-life doesn’t grow right without a soil additive: thallium oxide. Thallium must be more common in the galactic core than it is out here. Wherever the protectors spent a lot of their time, we’ll find thallium oxide for the plants. That’s how we’ll find the repair center. We’ll go in in pressure suits, if we ever get that far.”

The Hindmost’s voice exploded at them as they reached the road. “… LANDER! CHMEEE, LOUIS, WHAT ARE YOU HIDING? HINDMOST CALLING THE LAND—”

“Stop! Tanj dammit, turn down the volume, you’ll blow our ears out!”

“Can you still hear me?”

“We can hear you fine,” said Louis. Chmeee’s ears had folded into pockets of fur. Louis was wishing he could do that. “The mountains must have blocked us.”

“And what was it you discussed while we were cut off?”

“Mutiny. We decided against it.”

A momentary pause; then “Very wise,” said the Hindmost. “I want your interpretation of this hologram.”

One of the screens showed a kind of bracket poking out from the rim wall. The picture was slightly blurred, and oddly lit: taken in vacuum, in sunlight and light reflected from the Ringworld landscape on the right. The bracket seemed to be of a piece with the rim wall itself, as if scrith had been stretched like taffy. The bracket held a pair of washers or doughnuts separated by their own diameter. Nothing else showed save the top of the rim wall. It was impossible to guess the scale.

“This was taken from the probe,” the puppeteer said. “I have inserted the probe into the rim transport system, as advised. It is accelerating to antispinward.”

“Yah. What do you think, Chmeee?”

“It might be a Ringworld attitude jet. It would not be firing yet.”

“Maybe. There are a lot of ways to design a Bussard ramjet. Hindmost, do you get anything in the way of magnetic effects?”

“No, Louis, the machine seems dormant.”

“The superconductor plague wouldn’t have touched it in vacuum. It doesn’t look damaged. The controls could be somewhere else, though. On the surface. Maybe they can be repaired.”

“You would have to find them first. In the Repair Center?”

“Yah.”

The road ran between swampland and stony highlands. They passed what looked like another chemical plant. They must have been seen; there was a deep-throated foghorn sound and a blast of steam from what might have been a chimney. Chmeee didn’t slow down.

They saw no more of the boxy vehicles.

Louis had seen pale glimmers passing slowly among the trees, far into the swamp. They moved as slowly as mist on water, or as ocean liners docking. Now, far ahead, a white shape moved free of the trees and toward the road.

From a vast white bulk the beast’s sense-cluster rose on a slender neck. Its jaw was at ground level; it dropped like a shovel blade, scooping up swamp water and vegetation as the beast cruised uphill on rippling belly muscles. It was bigger than the biggest dinosaur.

“Bandersnatch,” Louis said. What were they doing here? Bandersnatchi were native to Jinx. “Slow down, Chmeee, it wants to talk to us.”

“What of it?”

“They’ve got long memories.”

“What would they remember? Swamp dwellers, muck-eaters, without hands to make weapons. No.”

“Why not? Maybe they could tell us what bandersnatchi are doing on the Ringworld in the first place.”

“That is no mystery. The protectors must have stocked their maps in the Great Ocean with samples of the species they considered potentially dangerous.”

Chmeee was playing dominance games, and Louis didn’t like it. “What’s the matter with you? We could at least ask!”

The bandersnatch dwindled behind them. Chmeee snarled, “You avoid confrontation like a Pierson’s puppeteer. Questioning muck-eaters and savages! Killing sunflowers! The Hindmost brought us to this doomed structure against our wills, and you delay our vengeance to kill sunflowers. Will it matter to the Ringworld natives a year from now that Louis the God paused in his passing to pull weeds?”