When Mack opened his eyes, he found he was on a busy street corner in what looked like a very large city. Mephistopheles and Marguerite were standing on either side of him. Mephistopheles was looking as dapper as always. He had a fresh red rosebud in the buttonhole of his dark lounge suit. His black shoes glittered with a new shine. And Marguerite was pretty as a picture. She'd found the time to repair her makeup since leaving Constantinople, and to change into a flowered gown with low-cut bodice.

Mack looked around, and saw at once that this city had many large and noble buildings of a peculiar design that had to be Chinese. This impression was further reinforced by the inhabitants, who, wearing silks and furs, and with their hands in their long sleeves, hurried back and forth holding high-pitched conversations. The air was crisp and cold and smelled of charcoal and five-spice powder. The sky overhead was a cold northern blue. Men in fur hats with flat orange faces passed by. These, Mack was pretty sure, were Mongols. There seemed to be a lot of them around, all armed to the teeth. They walked past Mack and the others as if they were not there.

"They can't see us," Mephistopheles said. "I have put us under a temporary Invisibility Spell. It's cheaper than hiring a conference room."

"If you say so," Mack said. "Now, what am I supposed to do here?"

"There in front of you," Mephistopheles said, "down at the end of the street, is the great palace of Kublai Khan. Within that palace live the great Khan, his nobles, relatives, concubines, and hangers-on. Also in that palace is Marco Polo."

"The famous Venetian explorer?" Mack asked.

"None other. His uncle and father would normally be there with him, but they've gone on a trading trip to Trebizond."

"Where's Trebizond?" Mack asked.

"Never mind. You don't need to know that. What you need to know is what you're supposed to do here."

"Yes, right," Mack said. "Better fill me in."

"The situation is like this. Marco is planning to leave Peking and return to Venice. Kublai Khan has reluctantly agreed to let him go because Marco is the only one who can provide safe escort for the Princess Irene, whom he has betrothed to one of his lords in Persia. There are plots 'gainst Marco's life, however. Some of the Mongol lords resent the favors Kublai has bestowed on him. There are people who want to kill him. One of your choices is to prevent Marco Polo from being killed before he leaves Peking."

"Now, wait a minute," Mack said. "He did leave Peking, didn't he?"

"Yes, but that was in the past. This is happening now. So it all must be done over again. And it could go a different way. Because even though it's happening over again, this is also the first time."

"But if it did go a different way," Mack said, "wouldn't that play hell with events in our own time?"

"You needn't worry about that," Mephistopheles said. "Think of it as a game within a game. You are brought here and given a moment in time. You will have three choices of what to do with that moment.

From your choices, we will see how you will affect the future, whether for good or for ill."

"No, it makes no sense at all," Mack said. "Why should I have to help Marco? He has already won out against any plot there might have been against him."

"You don't seem to understand," Mephistopheles said. "When we send you here, it's as if the story is happening for the first time. No outcomes are fixed. For that matter, who knows how many times the Marco Polo story has been replayed? The history of Earth is like the old morality plays one sees over and over again, but the outcomes are not fixed. It's like the commedia dell'arte. The basic cast assembles every evening, the situation is begun, but sometimes, quite unexpectedly, the outcome is different."

Marco Polo story has been replayed? The history of Earth is like the old morality plays one sees over and over again, but the outcomes are not fixed. It's like the commedia dell'arte. The basic cast assembles every evening, the situation is begun, but sometimes, quite unexpectedly, the outcome is different."

"

"How could you know what the main course of history is if you're immersed in its stream? And yet, although it is all deadly serious, it is all a game. At least, to us it is a game. But to you it had better stay serious or you'll suffer for it."

"What are my other choices?" Mack asked.

"There is the matter of the Princess Irene. She is from a far country and Kublai Khan has betrothed her to a lord of Persia. Yet if she were to marry someone else, that would change the course of history, too.

You can decide to change that by getting her to marry someone else."

"What happened with the one she did marry?" Mack asked. "History doesn't tell us," Mephistopheles replied.

"All right," Mack said. He saw he wasn't going to get anything much clearer out of this high-flown demon.

"And what is the third choice?" "Kublai Khan possesses a magic scepter that brings good luck to the Mongol forces, and hence bad luck on his enemies, which include the countries of the West that Kublai opposes. You could steal that scepter."

"I tried that last time with the magic icon."

"This time is completely different. Forget about the last time. Now, if you're quite ready, I'll take away the cloak of invisibility and you can begin."

"Wait a minute!" Mack said. "How do I explain my presence here?"

Mephistopheles pondered for a moment. "Tell them you're the ambassador from Ophir."

"And what is Ophir?"

"Ophir," Mephistopheles said, "is the city mentioned in the Old Testament from which King Solomon got his gold, silver, ivory, apes, and peacocks."

"And where is this Ophir located?"

"No one knows for sure. Various sites have been mentioned, among them East Africa, the Far East, Abyssinia, and Arabia. We can be sure Marco Polo has not been there, otherwise he would have mentioned it in the long and boastful list of travels he will leave behind. So you can safely claim your ambassadorship since there is no one to refute you."

"Well, all right," Mack said. "So I'm the Ophirian ambassador. Or is that Ophirese?"

"As you please," Mephistopheles said, showing signs of impatience. "Now, if you're quite ready?"

"Wait! One more thing," Mack said. "What about my clothing?"

"Look at yourself," Mephistopheles said.

Mack looked. Evidently, when redressing himself and Marguerite, Mephistopheles had found time to give Mack black-and-white tights, a wool-lined jacket, and a little cap with a feather in it. So that part was all right. But Mack felt there was something else, some other problem. Mephistopheles was beginning to make his disappearing gestures. Then Mack had it.

"What do you mean?" Mephistopheles said.

"Unless they know German and a little French, I'm going to be stuck."

"Oh." Mephistopheles frowned. "But, Dr. Faust, you are a renowned scholar and linguist."

"You know how it is," Mack said. "People exaggerate these things. Anyway, I've been a long time out of languages. They all need brushing up." "Very well," Mephistopheles said. "I'll give you a Language Spell that will enable you to understand everything anybody says. Be careful with it. It's not for general circulation."

"A magic Language Spell will help," Mack said.

Mephistopheles gestured. "It is done. You have to give it back when you are through with it."

"What about me?" Marguerite asked.

"You're just along as his friend," Mephistopheles said. "The Language Spell doesn't pertain to you. Ready, then?" Mack gulped and nodded. Mephistopheles disappeared, this time without a flash of fire and smoke, just a rather rapid fading out. At the same moment, a short, squat man with a long beard bumped into Mack.