Monk flinched. “You don’t know what you’re asking.” Now his voice was low. His eyes were hollow, only horror left.

Rathbone was truly afraid. “I’m asking for the truth.” He felt his throat so tight the words were forced out. “Why do you think this man is innocent? Nothing you’ve said so far makes sense of it. If he didn’t kill Hodge, who did and why? Are you saying it was one of the crew, or Louvain himself?” He jerked his hands, slicing the air. “Why would he? Why would a shipowner give a damn about one of his crewmen? What is it? Blackmail, mutiny, something personal? What would a shipowner have personal with a seaman? I’m no use to you half blind, Monk!”

Monk stood perfectly still, a momentous struggle raging inside him so clearly that Rathbone could only stand and watch, helpless and with a cold hand tightening inside him.

The clerk knocked on the door.

“Not yet!” Rathbone said tensely.

Monk focused his eyes; his face was even whiter than before. “You must listen. .” he said hoarsely, his voice a whisper.

Rathbone felt himself go cold. He brushed past Monk to the door, opened it and called for the clerk. The man appeared almost instantly.

“Cancel all my appointments for the rest of the day,” Rathbone told him. “An emergency has arisen. Apologize and tell them I will see them at their earliest convenience.” He saw the man’s face crease in bewilderment and dismay. “Do it, Coleridge,” he ordered. “Tell them I am very sorry, but the circumstances are beyond my control. And do not interrupt me or come to the door for any reason until I send for you.”

“Are you all right, Sir Oliver?” Coleridge asked with deep concern.

“Yes, I am. Just deliver my message, thank you.” And without waiting he went back into his office and closed the door. “Now. .” he said to Monk. “Tell me the truth.”

Monk seemed to have ceased struggling with his decision. He was even sitting down, as if exhaustion had finally taken him over. He looked so ashen Rathbone was afraid he was ill. “Brandy?” Rathbone offered.

“Not yet,” Monk declined.

This time it was Rathbone who could not sit down.

Monk began, looking not at Rathbone but somewhere in the distance. “Shortly after engaging me, Louvain took a woman to the clinic in Portpool Lane. I don’t know whether he knew of Hester from me, or if he knew of the clinic before, and possibly that was why he hired me rather than someone else. Don’t interrupt me! He said the woman was the cast-off mistress of a friend, which may or may not be true.” He ran his hand over his face. “Three days ago, in the evening, a rat catcher called Sutton came to me at home with a message from Hester.” At last he looked up at Rathbone and the pain in his eyes was frightening. “The woman, Ruth Clark, had died, and in dressing her for the undertaker, Hester discovered buboes in her armpits and groin.”

Rathbone had no idea what he was talking about. “Buboes?” he said.

“Black swellings,” Monk answered, his voice cracking. “They’re called buboes-that’s where we get the word bubonic.” He stopped abruptly.

The silence was as dense as fog while very slowly the meaning of what he had said sank into Rathbone and filled him with indescribable horror.

Monk was staring at him.

“Bubonic?” Rathbone whispered. “You don’t. . mean. .” He could not say it.

Monk nodded almost imperceptibly.

“But. . but that’s. . medieval. . it’s. .” Rathbone stopped again, refusing to believe it. He could not get his breath; his heart was hammering and the room was swaying around him, the edges of his vision blurred. He reached out his hands to grasp the desk as he overbalanced sideways and sat down hard and awkwardly, oblivious of bruising himself. “You can’t have that. . now! This is 1863! What do we do? How do they treat it? Who do we tell?”

“No one!” Monk said violently. He was between Rathbone and the door, and he looked as if he would physically prevent him from leaving, with force if necessary. “For God’s sake, Rathbone; Hester’s in there! If anyone got even an idea of it they’d mob the place and set fire to it! They’d be burned alive!”

“But we have to tell someone!” Rathbone protested. “The authorities. Doctors. We can’t treat it if no one knows!”

Monk leaned forward; his voice was shaking. “There is no treatment. Either they survive it or they don’t. All we can do is raise money to buy food, coal, and medicines for them. We have to contain it, at any cost at all. If we don’t, if even one person gets out carrying it, it will spread throughout London, throughout England, then the world. In the Middle Ages, before the Indian Empire or the opening up of America, it killed twenty-five million people in Europe alone. Imagine what it would do now! Do you see why we must tell no one?”

It was impossible, too hideous for the mind to grasp.

“No one!” Monk repeated. “They have men with pit bulls patrolling day and night, and anyone attempting to leave will be torn to pieces. Now do you see why I have to find out if the disease came in on the Maude Idris, and if Hodge died of the plague, and his head was beaten in so no one would think to look for any other cause of death? He was buried straightaway. I don’t know whether Louvain knew about him or the Clark woman or not. I have to find the source. I can’t let Gould be hanged for something he didn’t do, but not ever, even to save his life, can I tell what I know. Do you see?”

Rathbone found it almost impossible to move or speak. The room seemed to be far away from him, as if he were dreaming rather than seeing it. Monk’s face was the only steady thing in his sight, at once familiar and dreadful. Seconds ticked by in which he expected at any instant to wake up in a sweat and a tangle of bedclothes.

It did not happen. He heard hooves in the street outside, and the hiss of carriage wheels in the rain. Someone shouted. It was all real. There was no rescue, no escape.

“Do you see?” Monk repeated.

“Yes,” Rathbone replied at last. He was beginning to. There was no one to help; no one could. He frowned. “Nothing they can do? Doctors? Even now?”