“How did you get here?” asked Paphlagon.

“A commando raid on the concent of the Matarrhites. We have ways of dropping small capsules onto your planet that cannot be noticed by your sensors. A team of soldiers, as well as a few civilian experts such as myself, were sent down, and seized that concent. The true Matarrhites are held there, unharmed, but incommunicado.”

“That is an extraordinarily aggressive measure!” said Ignetha Foral.

“So it rightly seems to you who are not accustomed to encounters between different versions of the world, in different cosmi. But the Pedestal have been doing it for hundreds of years, and have become bold. When our scholars became aware of the Matarrhites, someone pointed out that their style of dress would make it easy for us to disguise ourselves and infiltrate the Convox. The order to proceed was given quickly.”

“How do you travel between cosmi?” Paphlagon asked.

“There is little time,” said Jules Verne Durand, “and I am no theor.” He turned to Suur Moyra. “You will know of a certain way of thinking about gravity, likely dating to the time of the Harbingers, called by us General Relativity. Its premise is that mass-energy bends spacetime…”

“Geometrodynamics!” said Suur Moyra.

“If the equations of geometrodynamics are solved in the special case of a universe that happens to be rotating, it can be shown that a spaceship, if it travels far and fast enough—”

“Will travel backwards in time,” said Paphlagon. “Yes. The result is known to us. We always considered it little more than a curiosity, though.”

“On Laterre, the result was discovered by a kind of Saunt named Godel: a friend of the Saunt who had earlier discovered geometrodynamics. The two of them were, you might say, fraas in the same math. For us, too, it was little more than a curiosity. For one thing, it was not clear at first that our cosmos rotated—”

“And if it doesn’t rotate, the result is useless,” said Paphlagon.

“Working in the same institute were others who invented a ship propelled by atomic bombs—sufficiently energetic to put this theory to the test.”

“I see,” said Paphlagon, “so Laterre constructed such a ship and—”

“No! We never did!”

“Just as Arbre never did—even though we had the same ideas!” Lio put in.

“But on Urnud it was different,” said Jules Verne Durand. “They had geometrodynamics. They had the rotating-universe solution. They had cosmographic evidence that their cosmos did in fact rotate. And they had the idea for the atomic ship. But they actually built several of them. They were driven to such measures because of a terrible war between two blocs of nations. The combat infected space; the whole solar system became a theatre of war. The last and largest of these ships was called Daban Urnud, which means ‘Second Urnud.’ It was designed to send a colony to a neighboring star system, only a quarter of a light-year away. But there was a mutiny and a change of command. It fell under the control of ones who understood the theorics that I spoke of. They chose to steer a different course: one that was intended to take them into the past of Urnud, where they hoped that they could undo the decisions that had led to the outbreak of the war. But when they reached the end of that journey, they found themselves, not in the past of Urnud, but in an altogether different cosmos, orbiting an Urnud-like planet—”

“Tro,” said Arsibalt.

“Yes. This is how the universe protects herself—prevents violations of causality. If you attempt to do anything that would give you the power of violating the laws of cause-and-effect—to go back in time and kill your grandfather—”

“You simply find yourself in a different and separate causal domain? How extraordinary!” said Lodoghir.

The Laterran nodded. “One is shunted into an altogether different Narrative,” he said, with a glance at Fraa Jad, “and thus causality is preserved.”

“And now it seems they’ve made a habit of it!” said Lodoghir.

Jules Verne Durand considered it. “You say ‘now’ as if it came about quickly and easily, but there is much history between the First Advent—the Urnudan discovery of Tro—and the Fourth—which is what we are all living through now. The First Advent alone spanned a century and a half, and left Tro in ruins.”

“Heavens!” exclaimed Lodoghir. “Are the Urnudans really that nasty?”

“Not quite. But it was the first time. Neither the Urnudans nor the Troans had the sophisticated understanding of the polycosm that you seem to have developed here on Arbre. Everything was surprising, and therefore a source of terror. The Urnudans became involved in Troan politics too hastily. Disastrous events—almost all of them the Troans’ own fault—played out. They eventually rebuilt the Daban Urnud so that both races could live on it, and embarked on a second inter-cosmic voyage. They came to Laterre fifty years after the death of Godel.”

“Excuse me,” said Ignetha Foral, “but why did the ship have to be changed so much?”

“Partly because it was worn out—used up,” said Jules Verne Durand. “But it is mostly a question of food. Each race must maintain its own food supply—for reasons made obvious by Fraa Erasmas’s experiment.” He paused and looked around the messal. “It is my destiny, now, to starve to death in the midst of plenty, unless by diplomacy you can persuade those on the Daban Urnud to send down some food that I can digest.”

Tris—who had returned to the messal early in the conversation—said, “We’ll do all we can to preserve the Laterran victuals that are still in the kitchen!” and hustled out of the room.

Ignetha Foral added, “We shall make this a priority in any future communications with the Pedestal.”

“Thank you,” said the Laterran, “for one of my ancestry, death by starvation would be the most ignominious possible fate.”

“What happened in the Second Advent—on Laterre?” asked Suur Moyra.

“I will skip the details. It was not as bad as Tro. But in every cosmos they visit, there is upheaval. The Advent lasts anywhere from twenty to a couple of hundred years. With or without your cooperation, the Daban Urnud will be rebuilt completely. None of your political institutions, none of your religions, will survive in their current form. Wars will be fought. Some of your people will be aboard the new version of the ship when it finally moves on to some other Narrative.”

“As you were, I take it, when it left Laterre?” asked Lodoghir.

“Oh, no. That was my great-grandfather,” said the visitor. “My ancestors lived through the voyage to Fthos and the Third Advent. I was born on Fthos. Similar things will probably happen here.”

“Assuming,” said Ignetha Foral, “that they don’t use the World Burner on us.”

I was just learning to read Laterran facial expressions, but I was certain that what I saw on Jules Verne Durand’s face was horror at the very mention. “This hideous thing was invented on Urnud, in their great war—though I must confess we had similar plans on Laterre.”

“As did we,” said Moyra.

“There is a suspicion, you see, planted deep in the minds of the Urnudans, that with each Advent they are finding themselves in a world that is more ideal—closer to what you would call the Hylaean Theoric World—than the last. I don’t have time to recite all the particulars, but I myself have often thought that Urnud and Tro seemed like less perfect versions of Laterre, and that Fthos seemed to us what we were to Tro. Now we are come to yet a new world, and there is terrible apprehension among the Pedestal that those of Arbre will possess powers and qualities beyond their grasp—even their comprehension. They have exaggerated sensitivity to anything that has this seeming—”

“Hence the elaborate commando raid, this ambitious ruse to learn about the Incanters,” said Lodoghir.