"Until the end, of course," Mack said.

"Of course. You could hardly miss noticing that."

Mack considered for a moment and then said, "You don't by any chance offer immortality, do you?"

"You drive a hard bargain, Faust! No, we don't offer immortality. Why should we? This new enhanced package of ours, limited as it may be in terms of what is possible to the imagination, is still enough to buy a trillion like you for the least part of it."

"How well you know us!" said Mack. "How wise you are!" But actually he thought that Mephistopheles was pompous, stuck-up, and more than a little silly. Mack felt he could handle this spirit, not knowing, of course, that he was falling for one of Hell's subtlest delusions.

"I just thought, if you had some immortality left over—I gather you don't need it yourself—how nice that must be—well, that you could throw some my way."

"But that would- defeat the whole purpose of my making you an offer. What profit is there for me unless I get your soul in the end?"

"You're right, of course, looking at it that way. Longevity is plenty good enough."

"That we offer, and rejuvenation as well."

"There is the matter of my soul."

"Bear in mind, the soul clause is a contingency deal. It comes into effect only if I fail to satisfy you completely over the course of our working together. Then you keep your soul, we shake hands, and go away friends. Can't say fairer than that, can I?"

"Hey, I'm not arguing," Mack said. "Now, what is it you want me to do?"

"We want you to play a part in a little contest my friends and I have devised."

"What sort of a contest is it?"

"One of the temporal-moral variety. We will put you into a series of situations in which you will play a part. Each episode will take place in its own distinct time and place. We will move to past or future, as the dictates of the game require. You will play a part in each episode. You will have a choice in each episode. How you make your choice, for what reasons, and with what end in mind, will be watched and judged. We will judge you, Faust, but not as you yourself, rather as a champion and exemplar of mankind, the one chosen by both of us to provide a reading on human morality, ethics, and other near-imponderable subjects. I say this very clearly to you, Faust, because I expect you to understand it before we begin. But once we start, you will not think much of the underlying awesomeness of the premises upon which this operates, for you will be too busy trying to watch out for your own skin."

"That is the bargain, Faust. The cast is ready, the scene is set behind the curtain, the players are all frozen into place, and the play is about to begin. We only wait for you to say the word."

He really is a long-winded devil, Mack thought. And Mephistopheles seemed something of an idealist despite his pretensions to cynicism. But there was no doubting the genuineness of the offer, nor was there any sense procrastinating with the dictates of his soul.

"I'm your man," he said. "Let's begin."

"Sign right here," Mephistopheles said, unrolling the slightly scorched parchment that he carried, proffering a quill and pointing his long sharpened fingernail at a vein in Mack's forearm.

The protagonists of the drama in Faust's chambers might, had they not been so involved in their own situation, have noticed a face that appeared momentarily at the one uncovered chamber window, then ducked down out of sight. It was Faust himself.

He had picked himself up in the Devil's Walk, his scalp bleeding from the Lett's powerful but clumsily directed blow. He had tottered for a moment, then sat down upon a curbstone to regain his senses. The Lett came out of the doorway then, and had raised his oaken cudgel to ensure a really deep unconsciousness, or perhaps death—whatever. A man couldn't be too finicky about these things, not in this day and age, not with the plague, ghastly in its gray cerements, raging in the south of Europe, not with Moslem warriors, bearing curved swords and imbued with an inexhaustible fanaticism, boiling up from Andalusia and threatening to break out again through the Pyrenees as in the days of Charlemagne, to wreak havoc on the soft cities of Languedoc and Aquitaine. These matters concerned the Lett not at all.

But before he had a chance to strike again there was a sound of full-throated men's voices lifted in lively dispute, and he knew it was university students, natural enemies to the caste that the Lett, all unknowingly, represented. They spotted him and raised the cry. The Lett took to his heels and raced away, to live to hit people over the head another day, and continued running until he was well clear of Cracow, at which time, seeing that he was on the road to Bohemia, he continued to the south, and so moved out of our story forever.

Faust was lifted to his feet by the students and brushed clean of the dirt and chicken entrails he had fallen into. Sewers in those days were no more than the dream-children of the most impractical of those architects who created our dark, cramped, smelly but friendly cities of the Dark Ages.

The voices wafted out the window, and insinuated themselves into Faust's ear.

It was at the point where Mack was about to sign his name in blood to the parchment Mephistopheles had brought that Faust came unglued. There was an impostor in his house! The devil was tempting the wrong man!

Faust turned from the window and raced around the house to the front. He entered, throwing back the heavy oak door so that it banged against the wall. Faust raced down the hallway, braked at his door, and threw it open.

He was just in time to catch Mack's final flourish as he signed the parchment. Then the devil rolled up the parchment, saying, "Now, my dear doctor, we will proceed to the Witches' Kitchen, where our expert cosmeticians will put you into condition for the adventures that lie ahead."

And then Mephistopheles raised his hands, flames sprang up, bright iris and violet flames, tinged here and there with sinister heliotrope, and flared in glory around the two figures. When they subsided the figures were gone.

"Damn!" Faust cried, running into the room, stopping, and pounding his fist into his palm. "One minute too late!"

Faust glared around into the gloom-shaded corners of his room. For a moment he thought he detected a presence among the bat-winged shapes in the ceiling. No, there was no one here. They had gone, the two of them, the impostor and Mephistopheles. Nothing remained but a faint smell of brimstone.

It was apparent to him what had happened. Through some miserable concatenation of circumstances, a stranger had broken into his chambers. It was that tall, yellow-haired zany whom he had glimpsed through the window. And Mephistopheles, that silly demon with the grandiose name, had somehow mistaken the fellow for him.

He frowned and shook his head. Faust had overheard enough to know that Mephistopheles had proposed some fine adventure, and was even now carrying the impostor away to it, and to rewards that belonged by right to Faust. And Faust was left alone in this dreary room, in this mundane city of Cracow, where he was supposed to carry on his life as though nothing had happened.

Well, damn it, he wasn't going to have it! He would go after them, if necessary to the nethermost realms of space and time, find Mephistopheles, expose the stranger for the impostor that he was, and take his rightful place in the glorious unfolding of things.

But then he considered for a moment. Was he ready for this? It would be a supreme test for any magician. And Faust, though he counted himself among the first rank in the controlling of the magical arts and the acquisition of esoteric knowledge, was not in his first youth. It might be beyond his powers. He might get himself killed…