"I"m so G.o.dd.a.m.ned tired, Mike."

"I know."

"I didn"t mean to yell at you like that."

"No offense taken, Joe."

"But I have trouble with this alternate-reality thing of yours. You think it was easy for me to believe that what we were doing here was talking to people in the past? But I brought myself around to it, weird though it was. Now you give it an even weirder twist, and it"s too much. It"s too rucking much. It violates my sense of what"s right and proper and fitting. You know what Occam"s razor is, Mike? The old medieval axiom, Never multiply hypotheses needlessly? Take the simplest one. Here even the simplest one is crazy. You push it too far."

"Listen," I said, "if you"ll just have someone drive me over to the hotel-"

"No."

"No?"

"Let me think a minute," he said. "Just because it doesn"t make sense doesn"t mean that it"s impossible, right? And if we get one impossible thing, we can have two, or six, or sixteen. Right?

Right?" His eyes were like two black holes with cold stars blazing at their bottoms. "h.e.l.l, we aren"t at the point where we need to worry about explanations. We have to find out the basic stuff first. Mike, I don"t want you to leave. I want you to stay here."

"What?"

"Don"t go. Please. I still need somebody to talk to the Mongol for me. Don"t go. Please, Mike? Please?"

The times, Temujin said, were very bad. The infidels under Saladin had smashed the Crusader forces in the Holy Land, and Jerusalem itself had fallen to the Moslems. Christians everywhere mourn the loss, said Temujin. In Byzantium- where Temujin was captain of the guards in the private army of a prince named Theodore Lascaris-G.o.d"s grace seemed also to have been withdrawn. The great empire was in heavy weather. Insurrections had brought down two emperors in the past four years and the current man was weak and timid. The provinces of Hungary, Cyprus, Serbia, and Bulgaria were all in revolt. The Normans of Sicily were chopping up Byzantine Greece and on the other side of the empire the Seljuk Turks were chewing their way through Asia Minor. "It is the time of the wolf," said Temujin. "But the sword of the Lord will prevail."

The sheer force of him was astounding. It lay not so much in what he said, although that was sharp and fierce, as in the way he said it. I could feel the strength of the man in the velocity and impact of each syllable. Temujin hurled his words as if from a catapult. They arrived carrying a crackling electrical charge. Talking with him was like holding live cables in my hands.

Hedley, jigging and fidgeting around the lab, paused now and then to stare at me with what looked like awe and wonder in his eyes, as if to say, You really can make sense of this stuff? I smiled at him. I felt bizarrely cool and unfl.u.s.tered. Sitting there with some electronic thing on my head, letting that terrific force go hurtling through my brain. Discussing twelfth-century politics with an invisible Byzantine Mongol. Making small talk with Genghis Khan. All right. I could handle it. I beckoned for notepaper. Need printout of world historical background late twelfth century, I scrawled, without interrupting my conversation with Temujin. Esp. Byzantine history, Crusades, etc.

The kings of England and France, said Temujin, were talking about launching a new Crusade.

But at the moment they happened to be at war with each other, which made cooperation difficult.

The powerful Emperor Frederick Barbarossa of Germany was also supposed to be getting up a Crusade, but that, he said, might mean more trouble for Byzantium than for the Saracens, because Frederick was the friend of Byzantium"s enemies in the rebellious provinces, and he"d have to march through those provinces on the way to the Holy Land.

"It is a perilous time," I agreed.

Then suddenly I was feeling the strain. Temujin"s rapid-fire delivery was exhausting to follow, he spoke Mongolian with what I took to be a Byzantine accent, and he sprinkled his statements with the names of emperors, princes, and even nations that meant nothing to me. Also there was that powerful force of him to contend with-it hit you like an avalanche-and beyond that his anger: the whip-crack inflection that seemed the thinnest of bulwarks against some unstated inner rage, fury, frustration. It"s hard to feel at ease with anyone who seethes that way.

Suddenly I just wanted to go somewhere and lie down.

But someone put printout sheets in front of me, closely packed columns of stuff from the Britannica. Names swam before my eyes: Henry II, Barbarossa, Stephan Nemanya, Isaac II (Angelos), Guy of Jerusalem, Richard the Lion-Hearted.

Antioch, Tripoli, Thessaloniki, Venice. I nodded my thanks and pushed the sheets aside.

Cautiously I asked Temujin about Mongolia. It turned out that he knew almost nothing about Mongolia. He"d had no contact at all with his native land since his abduction at the age of eleven by Byzantine traders who carried him off to Constantinople. His country, his father, his brothers, the girl to whom he had been betrothed when he was still a child- they were all just phantoms to him now, far away, forgotten. But in the privacy of his own soul he still spoke Khalkha. That was all that was left.

By 1187, I knew, the Temujin who would become Genghis Khan had already made himself the ruler of half of Mongolia. His fame would surely have spread to cosmopolitan Byzantium.

How could this Temujin be unaware of him? Well, I saw one way. But Joe had already shot it down. And it sounded pretty nutty even to me.

"Do you want a drink?" Hedley asked. "Tranks? Aspirin?"

I shook my head. "I"m okay," I murmured.

To Temujin I said, "Do you have a wife? Children?"

"I have vowed not to marry until Jesus rules again in His own land."

"So you"re going to go on the next Crusade?" I asked.

Whatever answer Temujin made was smothered by static.

Awkkk. Skrrkkk. Tsssshhhhhhh.

Then silence, lengthening into endlessness.

"Signal"s gone," someone said.

"I could use that drink now," I said. "Scotch."

The lab clock said it was ten in the morning. To me it felt like the middle of the night.

An hour had pa.s.sed. The signal hadn"t returned.

Hedley said. "You really think he"s Genghis Khan?"

"I really think he could have been."

"In some other probability world." Carefully I said, "I don"t want to get you all upset again, Joe."

"You won"t. Why the h.e.l.l not believe we"re tuned into an alternate reality? It"s no more goofy than any of the rest of this. But tell me this: is what he says consistent with being Genghis Khan?"

"His name"s the same. His age. His childhood, up to the point when he wandered into some Byzantine trading caravan and they took him away to Constantinople with them. I can imagine the sort of fight he put up, too. But his life-line must have diverged completely from that point on. A whole new world-line split off from ours. And in that world, instead of turning into Genghis Khan, ruler of all Mongolia, he grew up to be Petros- Alexios of Prince Theodore Lascaris"s private guards."

"And he has no idea of who he could have been?" Joe asked.

"How could he? It isn"t even a dream to him. He was born into another world that wasn"t ever destined to have a Genghis Khan. You know the poem: "Our birth is but a sleep and a forgetting: The soul that rises with us, our life"s star, Hath had elsewhere its setting, And cometh from afar."

"Very pretty. Is that Yeats?" Hedley said.

"Wordsworth," I said. "When"s the signal coming back?"

"An hour, two, three. It"s hard to say. You want to take a nap, and we"ll wake you when we have acquisition?"

"I"m not sleepy."

"You look pretty ragged," Joe said.

I wouldn"t give him the satisfaction.

"I"m okay. I"ll sleep for a week, later on. What if you can"t raise him again?"

"There"s always that chance, I suppose. We"ve already had him on the line five times as long as all the rest put together."

"He"s a very determined man," I said.

"He ought to be. He"s Genghis f.u.c.king Khan."

"Get him back," I said. "I don"t want you to lose him. I want to talk to him some more."

Morning ticked on into afternoon. I phoned Blaine twice while we waited, and I stood for a long time at the window watching the shadows of the oncoming winter evening fall across the hibiscus and the bougainvillea, and I hunched my shoulders up and tried to pull in the signal by sheer body English. Contemplating the possibility that they might never pick up Temujin again left me feeling weirdly forlorn. I was beginning to feel that I had a real relationship with that eerie disembodied angry voice coming out of the crackling night. Toward midafternoon I thought I was starting to understand what was making Temuijin so angry, and I had some things I wanted to say to him about that.

Maybe you ought to get some sleep, I told myself.

At half past four someone came to me and said the Mongol was on the line again.

The static was very bad. But then came the full force of Temujin soaring over it. I heard him saying, "The Holy Land must be redeemed. I cannot sleep so long as the infidels possess it."

I took a deep breath.

In wonder, I watched myself set out to do something unlike anything I had ever done before.

"Then you must redeem it yourself," I said firmly.

"I?" "Listen to me, Temujin. Think of another world far from yours. There is a Temujin in that world too, son of Yesugei, husband to Bortei who is daughter of Dai the Wise."

"Another world? What are you saying?"

"Listen. Listen. He is a great warrior, that other Temujin. No one can withstand him. His own brothers bow before him. All Mongols everywhere bow before him. His sons are like wolves, and they ride into every land and no one can withstand them. This Temujin is master of all Mongolia. He is the Great Khan, the Genghis Khan, the ruler of the universe."

There was silence. Then Temujin said, "What is this to me?"

"He is you, Temujin. You are the Genghis Khan."

Silence again, longer, broken by hideous shrieks of interplanetary noise.

"I have no sons and I have not seen Mongolia in years, or even thought of it. What are you saying?"

"That you can be as great in your world as this other Temujin is in his."

"I am Byzantine. I am Christian. Mongolia is nothing to me. Why would I want to be master in that savage place?"

"I"m not talking about Mongolia. You are Byzantine, yes. You are Christian. But you were born to lead and fight and conquer," I said. "What are you doing as a captain of another man"s palace guards? You waste your life that way, and you know it, and it maddens you. You should have armies of your own. You should carry the Cross into Jerusalem."

"The leaders of the new Crusade are quarrelsome fools. It will end in disaster."

"Perhaps not. Frederick Barbarossa"s Crusade will be unstoppable."

"Barbarossa will attack Byzantium instead of the Moslems. Everyone knows that."

"No," I said. That inner force of Temujin was rising and rising in intensity, like a gale climbing toward being a hurricane. I was awash in sweat, now, and I was dimly aware of the others staring at me as though I had lost my senses. A strange exhilaration gripped me. I went plunging joyously ahead. "Emperor Isaac Angelos will come to terms with Barbarossa. The Germans will march through Byzantium and go on toward the Holy Land. But there Barbarossa will die and his army will scatter-unless you are there, at his right hand, taking command in his place when he falls, leading them onward to Jerusalem. You, the invincible, the Genghis Khan."

There was silence once more, this time so prolonged that I was afraid the contact had been broken for good.

Then Temujin returned. "Will you send soldiers to fight by my side?" he asked.

"That I cannot do."

"You have the power to send them, I know," said Temujin. "You speak to me out of the air. I know you are an angel, or else you are a demon. If you are a demon, I invoke the name of Christos Pantokrator upon you, and begone. But if you are an angel, you can send me help. Send it, then, and I will lead your troops to victory. I will take the Holy Land from the infidel. I will create the Empire of Jesus in the world and bring all things to fulfillment. Help me. Help me."

"I"ve done all I can," I said. "The rest is for you to achieve."

There was another spell of silence.

"Yes," Temujin said finally. "I understand. Yes. Yes. The rest is for me."

"Christ, you look peculiar," Joe Hedley said, staring at me almost fearfully. "I"ve never seen you looking like this before. You look like a wild man."

"Do I?" I said.

"You must be dead tired, Mike. You must be asleep on your feet. Listen, go over to the hotel and get some rest. We"ll have a late dinner, okay? You can fill me in then on whatever you"ve just been jabbering about. We"ll have a late dinner, okay? But relax now. The Mongol"s gone and we may not get him back until tomorrow."

"You won"t get him back at all," I said.

"You think?" He peered close. "Hey, are you okay? Your eyes-your face-" Something quivered in his cheek. "If I didn"t know better I"d say you were stoned."

"I"ve been changing the world. It"s hard work."

"Changing the world?"

"Not this world. The other one. Look," I said hoa.r.s.ely, "they never had a Genghis Khan, so they never had a Mongol Empire, and the whole history of China and Russia and the Near East and a lot of other places was very different. But I"ve got this Temujin all fired up now to be a Christian Genghis Khan. He got so Christian in Byzantium that he forgot what was really inside him, but I"ve reminded him, I"ve told him how he can still do the thing that he was designed to do, and he understands. He"s found his true self again. He"ll go out to fight in the name of Jesus and he"ll build an empire that"ll eat the Moslem powers for breakfast and then blow away Byzantium and Venice and go on from there to do G.o.d knows what. He"ll probably conquer all of Europe before he"s finished. And I did it. I set it all in morion. He was sending me all this energy, this Genghis Khan zap that he has inside him, and I figured the least I could do for him was turn some of it around and send it back to him, and say, Here, go, be what you were supposed to be."

"Mike-"

I stood close against him, looming over him. He gave me a bewildered look.

"You really didn"t think I had it in me, did you?" I said. "You son of a b.i.t.c.h. You"ve always thought I"m as timid as a turtle. Your good old sober stick-in-the-mud pal Mike. What do you know? What the h.e.l.l do you know?" Then I laughed. He looked so stunned that I had to soften it for him a little. Gently I touched his shoulder. "I need a shower and a drink. And then let"s think about dinner."

Joe gawked at me. "What if it wasn"t some other world you changed, though? Suppose it was this one."

"Suppose it was," I said. "Let"s worry about that later. I still need that shower."