The laboring clerks clearly took pride in their work, and Yeh-lü treated them well, congratulating them on their prowess. But the clerks were slaves, Kolya learned, captured during the Mongols’ raids on the Chinese nations. Kolya had never met slaves before, and he couldn’t help but be fascinated by them. Their posture was always submissive, their eyes dropped, and the women especially cringed from any contact with the Mongols. Perhaps they were favored in the presence of Yeh-lü, but they were defeated, owned.

Kolya missed his home: his wife, his children, lost in the time streams. But each of these wretched slaves had been ripped from her home, her life trashed, and not by a godlike manipulation of time and space but simply through the cruelty of other human beings. The slaves’ plight didn’t make his own loss any easier to bear, but it warned him against self-pity.

If he found the presence of the slave clerks difficult to accept, Kolya took comfort in the civilized intelligence of Yeh-lü. After a time it seemed to him that he was finding it easier to trust Yeh-lü, a man from the thirteenth century, than Sable, a woman of his own time.

Sable grew impatient with the careful mapping sessions. And she was not impressed with the plans Yeh-lü was tentatively assembling to present to Genghis Khan.

The first priority ought to be consolidation, in Yeh-lü’s view. The Mongols had come to rely on the import of grain, cloth and many other essentials, and so trade had become important to them. As there were few working links left with China, the first and richest part of Genghis Khan’s Asiatic empire ought to be explored first. At the same time, Kolya urged, a party should be sent to the valley of the Indus, to seek out Casey and the other refugees from his own time.

But this wasn’t bold enough for Sable. After a week she walked into Yeh-lü’s chamber and stabbed a knife into the world map. The slave clerks fluttered away like frightened birds. Yeh-lü regarded her with cold interest.

Kolya said, “Sable, we are still strangers here—”

“Babylon,” she said. She pointed to her knife, which quivered at the heart of Iraq. “That’s where the Khan should be directing his energies. Grain stores, trade routes, the cowing of Chinese peasants—all these are dirt compared to that. Babylon is where the true power behind this new world lies—as you know as well as I do, Kolya—a manifestation of a power that has torn up space and time themselves. If the Khan gets hold of that, then his divine mission to rule the planet might come about after all, even in his lifetime.”

In English, incomprehensible to any of their interpreters, Kolya said, “Power like that, in the hands of Genghis Khan? Sable—you’re crazy.”

She looked at him, eyes blazing. “We’re eight centuries ahead, remember. We can harness these Mongols.” She waved her hand over the world map, as if laying claim to it. “It would take generations for anything like a modern civilization to be built on the fragments of history we have inherited. With the Mongols behind us we could shortcut that to less than a lifetime. Kolya, we can do this. In fact it’s more than an opportunity. It’s a duty. ”

Before this fierce woman, Kolya felt weak. “But this is a raging horse you’re trying to ride …”

Yeh-lü leaned forward. Through Basil he said, “You will speak in the common tongues.”

They both apologized, and Kolya repeated a sanitized version of the cosmonauts’ discussion.

Delicately Yeh-lü plucked the knife out of the gleaming map, and picked at the damaged threads. To Sable he said, “Your case is not made. Perhaps we could close our hand on the beating heart of the new world. But we cannot maintain that grip if we starve.”

She shook her head. “I will take this to the Khan. He would not be so timid as to pass by an opportunity like this.”

Yeh-lü’s face closed up, the nearest Kolya ever saw to him growing angry. “Emissary of Heaven, you do not yet have the ear of Genghis Khan.”

“Just wait,” Sable said in English, and she grinned defiantly, apparently without fear.

Answering Alexander’s summons they headed for the King’s tent: Captain Grove and his officers, Bisesa, Abdikadir, Cecil de Morgan in his role as interpreter, and Ruddy and Josh, who would record this astonishing conference in their notebooks. On the Macedonian side there would be Alexander himself, Eumenes, Hephaistion, the King’s doctor Philip and an inordinate number of courtiers, advisors, chamberlains and pages.

The setting was magnificent. Alexander’s official tent, hauled all the way from the delta, was immense, supported by golden columns and roofed with spangled cloth. Silver-legged sofas had been set up before the King’s golden throne for the visitors. But the atmosphere was tense: there must have been a hundred troops standing alert throughout the tent, the infantrymen known as Shield Bearers dressed in scarlet and royal blue, and Immortals from Persia in beautifully embroidered, if impractical, tunics.

Eumenes, seeking to minimize unnecessary friction, had quietly briefed Bisesa on the protocol expected in the King’s presence. So, on entering, the visitors from the future paid the King proskynesis, a Greek name for a Persian form of obeisance that involved blowing a kiss at the King and bowing. Abdikadir was predictably uncomfortable with this, but Captain Grove and his officers were unfazed. Evidently these British, stuck out on the edge of their own empire and surrounded by petty princes, rajahs and amirs, were accustomed to respecting eccentric local customs.

Aside from that, Bisesa could see that Abdikadir was enjoying himself hugely. She had met few people as hard-headed as Abdikadir, but he was obviously indulging himself in a pleasant fantasy that these magnificent Macedonians were indeed his ancestors.

The party settled on the magnificent couches, pages and ushers circulated with food and drink, and the conference began. The translation, channeled by Greek scholars and de Morgan, was slow and sometimes frustrating. But they got there steadily, sometimes with the aid of maps, drawings or even lettering scrawled on Macedonian wax tablets, or on bits of paper Ruddy or Josh ripped out of their notebooks.

They started with a sharing of information. Alexander’s people were not surprised by Jamrud’s Evil Eye, which continued to hover over the parade ground. Since “the day on which the sun had lurched across the sky,” as the Macedonians put it, their scouts had seen such things all over the Indus valley. Like the British, the Macedonians had quickly become used to these silent, floating observers, and treated them just as disrespectfully.

Hardheaded Secretary Eumenes was less interested in such silent mysteries than in the politics of the future, which had brought these strangers to the Frontier. It took some time to make Eumenes and the others understand that the British and Bisesa’s party were actually from two different eras—though the gap between them, a mere hundred and fifty years or so, was dwarfed by the twenty-four centuries between Alexander’s time and Bisesa’s. Still, as Captain Grove sketched in the background to the nineteenth-century Great Game, Eumenes showed his quick understanding.

Bisesa had expected her twenty-first-century conflict to be less comprehensible to the Macedonians, but when Abdikadir talked about central Asia’s oil reserves Eumenes spoke. He remembered that on the banks of a river in what Bisesa gathered was modern-day Iran, two springs of a strange fluid had welled out of the ground near where the royal tent had been pitched. “It was no different in taste or brightness from olive oil,” said Eumenes, “though the ground was unsuited to olive trees.” Even then, he said, Alexander had mused on the profit to be made out of such finds if they were extensive—though his tame prophet Aristander had declared the oil an omen of hard labor ahead. “We come here in our different times for our different ambitions,” said Eumenes. “But still we come, even across millennia. Perhaps this is the cockpit of the world for eternity.”