On the fourth day Roxanny told him to walk.

"Itll be another day yet," he told her.

"I know, but the diagnostics say youre nearly cured. Benefits of youth, I guess. Luis, soldiers turn out of the doc when they have to fight, and futz the diagnostics. It doesnt hurt them."

Louis was tempted, but — "Whats the hurry, Roxanny?"

"Wembleth says hes found a way in."

"Ah."

"Weve got a flycycle. It wont fly without you. Proserpina seems to have got it to fly itself, but I cant. Proserpina hasnt come back—"

"Wheres Hanuman?"

"Somewhere in the forest gorging on fruit, I think. Why?"

"He needs taking care of."

"No, he doesnt. Luis, I dont know what shes doing, but the joker wont stay away forever!"

So Louis climbed out of the ICC. He limped with one hand on Roxannys muscular shoulder, out to the flycycle where Wembleth was waiting. There were little sharp pains all through his left leg, hip, ribs.

Roxanny asked, "Will this thing hold three?"

"Sure, Wembleth can perch in the middle. Give me the front seat." Louis took his seat, wriggled carefully into a position of minimum pain. Wembleth crawled up between him and Roxanny. It was crowded, and the natives wild pelt brushed Louiss neck and ears.

He asked, "What did you find, Wembleth?"

"A path into the fortress," the wrinkled man said.

"Stet. Point me." Louis took off.

It wasnt symmetrical, or self-consciously artistic. It looked like a mountain — like the Matterhorn, all tilted planes done in dark stone, with a pervasive glitter from thousands of windows. A broad veldt surrounded the base, ending in a vertical cliff.

The veldt was a tilted plain of gold and black: lines and arcs of black grass on a field of gold. Louis asked, "What do you make of that?"

Wembleth said, "The black is dying back."

"Black isnt unreasonable for a plant," Roxanny said. "Chlorophyll throws away all the green light. What if a plant could use it all? There are some that do, in known space."

"Yah, but Wembleths right too. This looks like… writing thats been eroded, partly erased. How about this? Genetic engineering. The Penultimate planted it for decoration. Its just not as hardy as the hay, wheat, whatever."

From a height, the cliff did look artificial. Louis steered the flycycle close, then skimmed along the edge.

"This would stop plains apes," Roxanny said. "Not a flycycle."

"Nope. Do you feel lucky? Protectors are—"

"Territorial, yes, Luis. Wembleth, are we close?"

"Go more slow. Go up."

Louis took them up. "Here," Wembleth said when they were flying along the rim of the cliff. "Go left, starboard."

The tilted plain of grass might have been a lawn if it werent so big. Patterns shifted restlessly on its vast expanse. Wind? Louis borrowed Roxannys mag specs. With their aid he could make out thousands of creatures resembling yellow sheep.

Ahead, the rock barrier had fallen. Soil above had spilled after it. "Quake? Wembleth, what makes quakes on the Ringworld?"

Wembleth shrugged. Roxanny said, "Meteors?"

"I dont see a crater."

"Then try this, Junior. We have here a protector stronghold. What if some other protector wanted in?"

"Long, long ago," Louis said. A whole ecology, several varieties of grass and a puffball forest, had invaded the fallen rock and earth. "But that track is new."

It began as a series of scorched craters in the trees below the overgrown slope that had been a wall. The scattered dots became a dashed line of freshly chewed, carbonized earth as it rose up across the lawn and higher, into the curved walls of the Citadel itself.

"We werent wrong about defenses," Louis said. "Something climbed this slope, and weaponry fired on it all the way. Wembleth, how did you find this?"

"Roxanny sent me out to look around. The slope looked dangerous. Something must have done all this damage. I climbed a tree for a better look. Look, it goes all the way through those holes in the wall."

Roxanny said, "Follow that path and well be safe. All the booby traps are already triggered."

"You sure? Good, then I wont turn on the sonic shield."

"Youve got a shield of some kind? Stet, turn it on!"

"I was being sarcastic. Roxanny, its crazy to go in there. Thats a protectors castle. Theres no telling what games hes — what did she call him?"

"Penultimate. The next-to-last protector on this sea of maps. There could be a million years of miracles in there. Louis, we cant turn back now."

Its easy to be a coward when you cant fight and cant run. Louis looked behind him, seeking an ally. Wembleths posture urged him forward, as eager and impatient as Roxanny.

Louis flipped the sonic fold on. He couldnt see it working; they werent moving at anywhere near sonic speed.

Dark animals had been circling the yellow sheep, hidden beneath the grass. Now they streamed straight toward the flycycle, snarling crazily. They looked like dire wolves.

Theyd certainly stop Homo habilis who got this far. Louis skimmed above them, through cratered grass, following the path.

It was a time of surprises after ages of predictability. Proserpina brought the mag ship down at her base, and found:

No flycycle.

Everybody gone.

She found Hanuman among the fruit trees. He hadnt known that the flycycle was missing, but his guess was the same as Proserpinas. They ran for the mag ship and set it floating toward the Penultimates Citadel.

On the path of destruction Louis was following, they found places where the Penultimates own defenses had blasted away thick rock wall and left windows standing or fallen intact. The windows were hexagons about the size of a man. They were stronger than the stone. Diamond?

Louis could feel mechanical senses watching him.

He took the flycycle through a gap the size of a sailing yacht.

Sound struck at them. It was almost speech, a million angry voices yelling incomprehensibly, all muffled by the sonic fold. Light blazed at them, dimmed by the mag specs Louis had forgotten to take off. Behind him Wembleth and Roxanny both had heads bowed, tears running from their eyes. Louis looked for the nearest cover: a melted hole in a second wall. It looked too small for the sonic fold. He turned it off, screamed against the sound, went through, flipped it back on.

The roar eased, the light eased.

They were in a jumble of machinery, in a corridor twenty meters across and much higher. Some of the machines were tall and skeletal, like construction machinery. Many looked half-finished. The place looked like Tunesmiths workshop, or Brams, but more crowded.

Roxanny said, "I was hoping whatever went through here shot out the defenses." She was rubbing her eyes. Wembleth seemed okay. But -

"That stench!" Roxanny said. "Like a circus!"

She was right, though "Luis" would never have seen a circus. Wembleth said, "It smells like Blond Carnivores running a troll drive. I dont understand."

It was bad enough with the sonic fold keeping some of it out. Louis asked, "Pak planet panthers? That might drive away breeders, that and the lights and noise. I wonder what this smells like to a protector? That unwashed crowd stench could be someone elses children, millions of them. Maybe a thousand angry protectors smell like this. Thats it, its a warning for protectors."

Roxanny said, "Us too. Time to q—"

Wembleth jumped from the flycycle, dropped a meter, and landed with bent knees. He ran, weaving between machines and parts of machines, following the dashed line of melted floor. He looked back at the flycycle and happily waved them on.