“His father?”

“His divine father, Ammon, who is also Zeus, at his shrine in the desert.”

Abdikadir whistled. “That would be quite a tour.”

Eumenes smiled. “All the better. There is the question of Bisesa, too.”

“I know. She’s still locked away with that damn Eye.”

“I’m sure it’s invaluable work. But we don’t want to lose her to it: you moderns are too few to spare. Take her with you.” Eumenes smiled. “I hear that Josh is back from Judea. Perhaps he might distract her …”

“You’re a wily devil, Secretary Eumenes.”

“One does what one must,” said Eumenes. “Come. I’ll show you round the shipyards.”

The temple chamber was a rat’s nest of cables and wires and bits of kit from the crashed chopper, some of them scarred where they had been crudely cut from the wreck, or even scorched by the fires that had followed the crash. This tangle enclosed the Eye, as if Bisesa had been seeking to trap it, not study it. But she knew that Abdikadir thought it was she who had become trapped.

“The Discontinuity was a physical event,” Bisesa said firmly. “No matter how mighty the power behind it. Physical, not magical or supernatural. And so it’s explicable in terms of physics.”

“But,” said Abdikadir, “not necessarily our physics.”

She glanced vaguely about the temple chamber, wishing she still had the phone to help her explain.

Abdikadir, and a wide-eyed, scared-looking Josh, had settled down in a corner of the chamber. She knew Josh hated this place—not just for the awesome presence of the Eye, but because it had taken her away from him. Now Josh cracked a flask of hot tea with milk, English-style, as Bisesa tried to explain her current theories about the Eye, and the Discontinuity.

Bisesa said, “Space and time were ruptured during the Discontinuity—ruptured and put back together again. We know that much, and in a way we can understand it. Space and time are in some senses real .You can bend space-time, for instance, with a strong enough gravity field. It’s as stiff as steel, but you can do it …

“But if space-time is stuff, what’s it made of? If you look really closely—or if you subject it to enough bending and folding—well, you can see the grain. Our best idea is that space and time are a kind of tapestry. The fundamental units of the tapestry are strings, minuscule strings. The strings vibrate—and the modes of the vibration, the tones of the strings, are the particles and energy fields we observe, and their properties, such as their masses. There are many ways the strings can vibrate—many notes they can play—but some of them, the highest energy modes, have not been seen since the birth of the universe.

“All right. Now, the strings need a space to vibrate in—not our own space-time, which is the music of the strings, but a kind of abstraction, a stratum. In many dimensions.”

Josh frowned, visibly struggling to keep up. “Go on.”

“The way the stratum is set up, its topology, governs the way the strings behave. It’s like the sounding board of a violin. It’s a beautiful image if you think about it. The topology is a property of the universe on the largest scale, but it determines the behavior of matter on the very smallest scales.

“But imagine you cut a hole in the sounding board—make a change to the structure of the underlying stratum. Then you would get a transition in the way the strings vibrate.”

Abdikadir said, “And the effect of such a transition in the world we observe—”

“The strings’ vibrations govern the existence of the particles and fields that make up our world, and their properties. So if you go through a transition, those properties change.” She shrugged. “The speed of light might change, for instance.” She described her measurements of Doppler shifts in the reflections from the Eye of Marduk; perhaps that was something to do with stratum-level transitions.

Josh leaned forward, his small face serious. “But, Bisesa—what about causality? You have the Buddhist monk, who Kolya described, living with his own younger self! Now, what if that old man were to strangle the boy—would the lama pop out of existence? And then there is poor Ruddy—dead, now, and so forever incapable of writing the novels and poems that you claimed, Bisesa, to have stored in your phone! What does your physics of strings and sounding-boards say about that?”

She sighed and rubbed her face. “We’re talking about a ripped-apart space-time. The rules are different. Josh, do you know what a black hole is? … Imagine a star collapsing, becoming so dense that its gravity field deepens hugely—in the end, not even the most powerful rocket could escape from its grasp—in the end, even light itself can’t escape. Josh, a black hole is a tear in the orderly tapestry of space-time. And it eats information. If I throw an object into a black hole—a rock, or the last copy of the complete works of Shakespeare, it doesn’t matter—almost all the information about it is lost, beyond retrieval, nothing but its mass, charge and spin.

“Now, the interfaces between the chunks of Mir, drawn from different eras, were surely not like the event horizons of black holes. But they were space-time rips. And perhaps information is lost in the same way. And that’s why causality has broken down. I think our new reality, here on Mir, is—knitting up. New causal chains are forming. But the new chains are part of this world, this reality, and have nothing to do with the old …” She rubbed tired eyes. “That’s the best I can do. Depressing, isn’t it? Our most advanced physics offers us nothing but metaphors.”

Abdikadir said gently, “You must write this down. Have Eumenes assign you a secretary to record it all.”

“In Greek?” Bisesa laughed hollowly.

Josh said, “We are talking of the how of the Discontinuity. I am no closer to understanding the why .”

“Oh, there was a purpose,” said Bisesa. She glared up at the Eye resentfully. “We just haven’t figured it out yet. But they are up there, somewhere—beyond the Eye, beyond all the Eyes—watching us. Playing with us, maybe.”

“Playing?”

She said, “Have you seen the way the Eye in the cage has been experimenting with the man-apes? They run around that damn net like rats with wires in their heads.”

Josh said, “Perhaps the Eye is trying to—” He spread his hands. “Stimulate the man-apes. Uplift them to greater intelligence.”

“Look in their eyes,” said Bisesa coldly. “This has nothing to do with uplift. They are draining those wretched creatures. The Eyes aren’t here to give. They are here to take.”

“We are no man-apes,” said Abdikadir.

“No. But maybe the tests they are running on us are just more subtle. Maybe the peculiar features of the Eye, like its non-Euclidean geometry, are there solely as a puzzle-box for us. And you think it was a coincidence that Alexander and Genghis Khan were both brought here? The two greatest warlords in Eurasian history, knocking their heads together, by chance? They are laughing at us. Maybe that’s all there is to this whole damn thing.”

“Bisesa .” Josh took her hands in his. “You believe the Eye is the key to everything that is happening. Well, so do I. But you are letting the work destroy you. And what good will that do?”

She looked at him and Abdikadir, alarmed. “What are you two cooking up?”

Abdikadir told her about Alexander’s planned European expedition. “Come away with us, Bisesa. What an adventure!”

“But the Eye—”

“Will still be here when you get back,” Josh said. “We can delegate somebody else to continue your monitoring.”

Abdikadir said, “The man-apes can’t leave their cage. You are a human. Show this thing it can’t control you, Bisesa. Walk out.”

“Bullshit,” she said tiredly. Then she added, “Casey.”

“What?”

“Casey’s got to run this shop. Not some Macedonian. And not some British, who would be worse, because he’d think he understands.”