They nodded. "Yes, Master," Hakim Fadil ibn Parviz said tremulously, speaking for all in his new position. Young Ali was weeping silently. Karim Harun's handsome face was dark with foreboding.

Finally Mirdin Askari spoke up. "My wife and children ... I must make arrangements. To be certain they'll be all right if ..."

Ibn Sina nodded. "Those of you with responsibilities have only brief hours to make these arrangements."

Rob hadn't known Mirdin was married and a father. The Jewish clerk was private and self-reliant, sure of himself in the cla.s.sroom as well as in the maristan. But now his lips were bloodless, and moved in silent prayer.

Rob J. was as frightened as any at being sent on this errand from which there might be no return, but he struggled for courage. At least he would no longer have to serve as leech at the jail, he told himself.

"One thing more," Ibn Sina said, gazing at them with a parent's eyes. "You must keep careful notes, for those who will fight the next plague. And you must leave them where they will be found if something should happen to you."

Next morning, as the sun bloodied the tops of the trees they clattered over the bridge across the River of Life, each man on a good horse and leading either a packhorse or a mule.

After a while Rob suggested to Fadil that one man be sent ahead as scout and another ride far back as rear guard. The young hakim pretended to consider and then he bawled out the orders.

That night Fadil agreed at once when Rob suggested the same system of alternating sentries that had been employed by Kerl Fritta's caravan.

Seated around a thornbush fire, they were by turns jocular and grim.

"I believe Galen was never so wise as when he considered a physician's best choice of action during plague," Suleiman-al-Gamal said darkly. "Galen said a physician should flee the plague, to live to treat another day, and that is exactly what he did himself."

"I believe the great physician Rhazes said it better," Karim said.

"Three little words the plague dispel:

Quick, far and late, where'er you dwell.

Start quick, go far and right away,

And your return till late delay."

Their laughter was too loud.

Suleiman was their first sentry. It should have been no great surprise the following morning when they awoke to discover he had slipped away during the night, taking his horses with him.

It shook them and filled them with gloom. When they made camp the following evening, Fadil named Mirdin Askari to be sentry, a good choice; Askari guarded them well.

But the sentry at their third camp was Omar Nivahend, who emulated Suleiman and fled with his horses during the night.

Fadil called a meeting as soon as the second desertion was discovered.

"It's no sin to be afraid of the Death, else each of us is eternally d.a.m.ned," he said. "Nor, if you agree with Galen and Rhazes, is it a sin to flee-though I side with Ibn Sina in thinking a physician should fight pestilence instead of showing it his heels.

"What is a sin is to leave your companions unguarded. And it is worse to steal off with a pack animal bearing supplies needed by the sick and the dying." He gazed at them levelly. "Therefore, I say that if anyone else wishes to leave us, let him go now. And I promise on my honor that he will be allowed to do so without shame or prejudice."

They could hear each other's breathing. No one came forward.

Rob spoke up. "Yes, anyone should be allowed to go. But if the departure leaves us sentryless and unguarded, or if he takes with him supplies needed by the patients toward whom we travel, I say we must ride after such a deserter and kill him."

Again there was a silence.

Mirdin licked his lips. "I agree," he said.

"Yes," Fadil said.

"I agree also," said Abbas Sefi.

"And I," Ali whispered.

"And I!" said Karim.

Each of them knew it was no empty promise, but a solemn vow.

Two nights later, it was Rob J.'s turn to serve as sentry. They had made camp in a stony defile where moonshine created monsters of the looming rocks. It was a long and lonely night that gave him opportunity to think of sad things he otherwise managed to crowd out of his mind, and he dwelt on his brothers and his sister, and on those who were dead. He had long thoughts about the woman he had allowed to drift through his fingers.

Toward morning he was standing in the shadow of a great rock, not far from the sleeping men, when he became aware that one of them was awake and appeared to be making preparations for leaving.

Karim Harun stole through the encampment, taking care not to disturb the sleepers. When he was clear, he began to run lightly down the trail, and soon he was out of sight.

Harun had neither taken supplies nor left the party unguarded, and Rob made no attempt to stop him. But he felt a bitter disappointment, for he had begun to like the handsome and sardonic clerk who had been a medical student for so many years.

Perhaps an hour later he drew his sword, alerted by the sound of pounding footsteps coming toward him in the gray light. He stood and confronted Karim, who stopped in front of him and gaped at the ready blade, his chest heaving and his face and tunic wet with sweat.

"I saw you leave. I believed you had run away."

"I did." Karim fought for breath. "I ran away ... and I ran back. I am a runner," he said, and smiled as Rob J. put away his sword.

Karim ran every morning, returning to them drenched in sweat. Abbas Sefi told comical stories and sang filthy songs and was a cruel mimic. Hakim Fadil was a wrestler, and in their camps at night the leader threw them all, having trouble only with Rob and with Karim. Mirdin was the best cook among them and cheerfully accepted the duty of preparing the evening meals. Young Ali, who had Bedouin blood, was a dazzling horseman and loved nothing better than serving as scout, ranging far ahead of the party; soon his eyes shone with enthusiasm instead of tears and he displayed a youthful energy that endeared him to all.

Their growing companionship was pleasant and the long ride might have been enjoyable except that, in camp and during rest pauses, Hakim Fadil read to them from the Plague Book that Ibn Sina had entrusted to him. The book offered hundreds of suggestions by various authorities, all of whom claimed to know how to fight the plague. A man named Lamna of Cairo insisted that an infallible method was to give the patient his own urine to drink, at the same time reciting specified imprecations to Allah (glorified is He!).

Al-Hajar of Baghdad suggested the sucking of an astringent pomegranate or plum at the time of an epidemic, and Ibn Mutillah of Jerusalem strongly recommended the eating of lentils, Indian peas, pumpkin seeds, and red clay. There were so many suggestions that each was made worthless to the bewildered medical party. Ibn Sina had written an addendum to the book, in which he had listed practices that seemed reasonable to him: the lighting of fires to create acrid smoke, washing down walls with limewater, sprinkling vinegar, and giving victims fruit juices to drink. In the end, they agreed to follow the regimen suggested by their teacher and to ignore all other advice.

During a pause in the middle of the eighth day Fadil read from the book that, of every five physicians who had treated the Death during the Cairo plague, four had themselves died of the disease. A quiet melancholy took hold of them as they resumed the ride, as if they had been informed of the sealing of their fate.

Next morning they came to a small village and learned it was Nardiz and that they had entered the district of Anshan.

The villagers treated them respectfully when Hakim Fadil announced they were physicians from Ispahan, sent by Al Shah to help those afflicted by the plague.

"We do not have the pestilence, Hakim," the head of the village said thankfully. "Although rumors have reached us of death and suffering in Shrz."

Now they traveled expectantly, but they pa.s.sed village after village and saw healthy people. In a mountain valley at Naksh-i-Rustam, they came to great rock-hewn tombs, the burial place of four generations of Persian kings. Here, overlooking their windswept valley, Darius the Great, Xerxes, Ataxerxes, and Darius II had lain for fifteen hundred years during which wars, pestilences, and conquerors had come and faded into nothingness. While the four Muslims paused for Second Prayer, Rob and Mirdin stood before one of the tombs in wonder as they read the inscription: I AM XERXES THE GREAT KING, THE KING OF KINGS,.

THE KING OF COUNTRIES OF MANY RACES,.

THE KING OF THE GREAT UNIVERSE, THE SON OF DARIUS THE KING,.

THE ACHAEMENIAN.

They rode past a great ruined place of broken fluted columns and strewn stone. Karim told Rob it was Persepolis, destroyed by Alexander the Great nine hundred years before the birth of the Prophet (may G.o.d bless him and greet him!).

A short distance from the ancient remains of the town they came to a farm. It was quiet save for the bleating of a few sheep grazing beyond the house, a pleasant sound that carried cleanly through the sunlit air. A shepherd seated beneath a tree appeared to be watching them, and when they rode up to him they saw he was dead.

The hakim just sat his horse like the rest of them, staring at the body. When Fadil failed to take the lead, Rob dismounted and examined the man, whose flesh was blue and already hard and stiff. He had been dead too long for his staring eyes to be closed, and an animal had been gnawing at his legs and had eaten away his right hand. The front of his tunic was black with blood. When Rob took his knife and cut open the garment he could find no sign of plague but there was a stab wound over the heart, large enough to have been made by a sword.

"Search," Rob said.

The house proved to be deserted. In the field beyond, they found the remains of several hundred slaughtered sheep, many of the bones already picked clean by wolves. All about, the field was greatly trampled, and it was apparent that an army had stopped there long enough to kill the shepherd and take meat.

Fadil, his eyes gla.s.sy, didn't give a direction or an order.

Rob lay the body on its side and they mounded it over with stones and large rocks to preserve the rest of it from the beasts, then they were glad to ride from that place.

Eventually they came to a fine estate, a sumptuous house surrounded by cultivated fields. It too appeared deserted, but they dismounted.

After Karim had knocked loudly and long, a peephole in the center of the door was opened and an eye stared out at them.

"Begone."

"We are a medical party from Ispahan, bound for Shrz," Karim said.

"I am Ishmael the Merchant. I can tell you few remain alive in Shrz. Seven weeks ago, an army of Seljuk Turkomen came to Anshan. Most of us fled before the Seljuks, taking women, children, and animals within the Shrz walls. The Seljuks beleaguered us. The Death already had broken out among them and they gave up the siege within a few days. But before they departed they sent the bodies of two of their plague-dead soldiers over the walls by catapult, into the crowded town. As soon as they were gone, we hastened to take the two corpses outside the wall and burn them, but it was too late, and the Death appeared among us."

Now Hakim Fadil found his tongue. "Is it a fearsome pestilence?"

"No worse can be imagined," said the voice behind the door. "Some persons appear to be immune to the disease, as was I, thanks be to Allah (whose mercy abounds!). But most who were within the walls are dead or dying."

"What of the physicians of Shrz?" Rob asked.

"There were in the town two barber-surgeons and four physicians, all other leeches having fled as soon as the Seljuks departed. Both barbers and two of the physicians labored among the people until they too were dead, and quickly. One leech was down with the disease and only a single physician remained to care for the afflicted when I abandoned the city myself, not two days since."

"Then it appears that we are badly needed in Shrz," Karim said.

"I have a large clean house," the man said, "stocked with ample supplies of food and wine, vinegar and lime, and a plentiful store of hemp plant to chase away troubles. I would open this house to you, for it is my protection to let in healers. In but a little while, when the pestilence has run its course, we can enter Shrz to our mutual profit. Who will join my safety?"

There was a silence.

"I," Fadil said hoa.r.s.ely.

"Do not do this, Hakim," Rob said.

"You are our leader and our only physician," Karim said.

Fadil didn't appear to hear them. "I shall come inside, merchant."

"I shall come inside too," Abbas Sefi said.

Both men slid from their horses. There was the sound of a heavy bar being eased slowly free. They glimpsed a pale, bearded face as the door opened only far enough to allow the two men to slip inside, then it was slammed again and barred.

Those outside stood like men adrift on the open sea. Karim looked at Rob. "Perhaps they are right," he muttered. Mirdin said nothing, his face troubled and uncertain. The youth Ali was about to weep again.

"The Plague Book," Rob said, remembering that Fadil carried it in a large purse he wore on a strap around his neck. He went to the door and hammered on it.

"Go away," Fadil said. He sounded terrified; doubtless he feared to open the door lest they fall on him.

"Hear me, you s.h.i.tepoke," Rob said, seized by fury. "If we are not given Ibn Sina's Plague Book, wood and brush will be gathered and piled high against the walls of this house. And I will delight in setting it afire, you false physician."

In a moment the drawing of the bar was heard again. The door opened and the book was thrown out to fall in the dust at their feet.

Rob picked it up and mounted. His fury didn't last as he rode away, for part of him yearned to be with Fadil and Abbas Sefi in the merchant's safe place.

He traveled a long time before he could bring himself to turn in the saddle. Mirdin Askari and Karim Harun were far back, but coming after him. The youth, Ali Rashid, brought up the rear, leading Fadil's packhorse and Abbas Sefi's mule.