“How do you know that?” he repeated the demand. “What have you heard? From whom—Dalgarno?”

  “Dalgarno?” she said incredulously, then she started to laugh, a wild sound, close to hysteria. But she did not answer. Instead, she turned away from him again and half ran along York Gate towards the Marylebone Road and the general traffic with carriages and hansoms going in both directions. “I’m going home!” she called at him over her shoulder.

  He ran after her, catching up again and walking beside her as she reached the road and raised her parasol to hail a cab. One pulled up almost immediately and Monk helped her in, climbing in after her.

  She made no protest, almost as if she had expected him to.

  “If it was not Dalgarno, then from whom?” he insisted after she had given the driver instructions to take her to Cuthbert Street in Paddington.

  She turned to face him. “You mean the fraud case, all those years ago?”

  “Yes, of course I do!” He kept his temper only with the greatest difficulty. It mattered intensely. What did she know? How could she know anything, except from Baltimore’s records or something she had overheard him say?

  She stared straight ahead, smiling, but there was a hollowness in her eyes. “Did you imagine I made no enquiries myself, Mr. Monk?” Her voice was hard-edged, grating. “Did you think I learned nothing about the past history of Baltimore and Sons when I knew how deeply Michael was involved in it, and expected to make his fortune through it?”

  “You said that you knew an innocent man was convicted of fraud in that case,” he said grimly, horrified at how his own voice betrayed the emotion choking him. “How do you know that? No one knew it then.”

  “Didn’t they?” she asked, staring ahead of her.

  “Of course they didn’t, or he wouldn’t have died in jail!” He grasped her arm. “How do you know? What happened?”

  She turned in the seat to stare at him, her face twisted with a fury so intense he drew back from it, loosening his hold on her.

  “A great wrong, Mr. Monk,” she said softly, her voice trembling, her words almost a hiss. “People were wronged then, and are wronged now. But revenge will come—that I promise you. It will come . . . on my mother’s grave . . . on mine if need be.”

  “Miss Harcus . . .”

  “Please get out!” Her face was ashen now. “I need to think, and I must do it alone.” She snatched her hand from him and, picking up the parasol, banged on the front of the hansom to draw the driver’s attention. “I will tell you . . . this evening.”

  She banged on the front again, more fiercely.

  “Yes, miss?” the driver answered.

  “Mr. Monk is alighting. Would you be so good as to stop,” she ordered.

  “Yes, miss,” he said obediently, and pulled in to the curb. They were at the corner of Marylebone Street and the Edgware Road, traffic streaming around them in both directions.

  Monk was touched by a deep concern for her. She looked so torn by conflicting passions it was almost as if she had a fever. He wanted desperately to know what she meant by stating so vehemently that Dundas was innocent and that revenge would come, or what the present wrong was that he could not see. But now that he knew where she lived at least he could find her again when she was calmer. Perhaps he could even be of some help to her. Now she needed to rest and compose herself.

  “I’ll call upon you, Miss Harcus,” he said far more gently. “Of course, you need time to consider.”

  She made an intense effort at self-control, breathing in very deeply and letting it out in a sigh. “Thank you, Mr. Monk. That would be very good of you. You are most patient. If you would call upon me this evening—after eight, if you would be so good—then I shall tell you what you wish. I shall speak to Michael Dalgarno again, and that will be the end of it, I promise. You have played your part perfectly, Mr. Monk. I could not have wished better. You will see me after eight? Do you give me your word—absolutely?”

  “I do,” he swore.

  “Good.” The faintest ghost of a smile touched her face. “At twenty-three Cuthbert Street. You have given me your word!”

  “Yes. I will be there.”

  He alighted and stood on the pavement as the hansom pulled away from the curb immediately and was lost in the traffic.

  Monk went home to Fitzroy Street and an empty house. He washed and slept at last. At ten past eight, as the light was fading, he took a hansom to twenty-three Cuthbert Street. He was startled back to attention from his thoughts when they stopped abruptly and the cabbie looked in and told him that he could not go any further.

  “Sorry, sir,” he said apologetically. “P’lice blockin’ the road. Dunno wot’s ’appened, but there’s a big ruckus up front. Can’t go no further. Yer’ll ’ave ter walk, if they’ll let yer.”

  “Thank you.” Monk scrambled out, paid him, leaving the change of eight pence, and started to walk toward figures he could see standing under the street lamps. There were three men, two arguing with each other, the third, familiar in its tall, stiff outline, looking down at something like a bundle of clothes that lay at his feet. It was Runcorn, who had been Monk’s rival in the old days, then his superior; who had always hated and feared him until the quarrel when he had dismissed Monk at the same moment Monk had resigned in fury. Then the case of the artist’s model just months before had drawn them together again, and in shared emotions, painful and unexpected pity, they had formed an uneasy alliance.

  But what was Runcorn doing here?

  Monk lengthened his stride, only just restraining himself from running the last few yards.

  “What is it?” he demanded, although as Runcorn swung around to face him, he could already see. The figure of a woman was sprawled on the ground. Her white muslin dress trimmed in blue was crumpled, and dirty, and deeply stained with blood. She lay half on her front, half sideways, as if she were broken. Her neck was at an awkward angle, one arm doubled under her, her legs crooked.

  Instinctively, he looked upward and saw the flat roof of the building’s third floor, and then the rest of it going up another story beyond that. There was a railing as if it were an extended balcony from the upstairs room. He could not see the door; it was hidden by the wall above them.

  A wave of nausea overtook him, and then overwhelming, consuming pity. He stared at Runcorn, his mouth too dry to speak.

  “Looks like she fell off,” Runcorn replied to Monk’s original question. “Except she’s a bit far out, as the eye sees it. And people usually fall backward. Might have twisted in the air.” He squinted upward. “It’s a fair distance. Get a better idea from up there. Could’ve jumped, I suppose.”

  Monk started to speak, then stopped.

  “What is it?” Runcorn asked sharply.

  “Nothing,” Monk said hastily. He should say nothing . . . not yet. His mind raced. What on earth could have happened? She would never, ever have jumped! Not Katrina Harcus. She was on the edge of exposing an ancient wrong. She wanted revenge, and she had had it almost within her grasp. And Dalgarno was innocent, which was what she had wanted above all from the beginning.

  A uniformed constable came across the pavement, pushing his way past the bystanders who had begun to gather. “Got a witness, sir,” he said to Runcorn. His face was pinched and unhappy, expression exaggerated in the shadows cast by the street lamp. “Says there were two people up there, quite definite. ’E saw them strugglin’ back and forward. ’Eard ’er scream out summink, and then she staggers back an’ ’e comes after ’er, an’ next thin’ ’e turns, an’ she’s gorn over the edge.” He looked down at the figure on the ground. “Poor creature. Looks like she were youn’ . . . an’ right ’andsome too. It’s a cryin’ shame.”

  “What happened to the man?” Runcorn asked, glancing at Monk, then back to the constable.

  The constable straightened up. “Dunno, sir. I asked the witness but ’e didn’t see. Light was very fitful, like. ’E saw ’er partic’lar because of ’er wearin’ white an’ all. Man were in summink very dark, an’ ’e’ad a cloak on, sort o’ . . .” He shrugged. “Well, a cloak. Witness says ’e saw it billowin’ out when they was fightin’ just before she went over.”

  Monk felt sick imagining it, Katrina struggling with someone, crying out for help, and no one did more than watch! They did not even know who had been there on the roof fighting with her . . . killing her! Dalgarno? It must have been. He was the only person involved. He must have come here when she had contacted him, as she had told Monk she would. Something she had said, some evidence she had found and he had missed, for all his meticulous searching, had driven Dalgarno to defend himself this murderous way.

  But what? How had he committed the fraud? Why had Monk not been able to find it? Why was he so stupid, so blind all over again? And now someone else was dead, another he had been doing everything he could to help. He had promised her . . . and failed.

  Runcorn was still talking to the constable. Monk bent onto his knees beside the body. Her eyes were wide open. This side of her face was barely damaged at all; there was just a trickle of blood. He knew better than to touch her, but he wanted to brush back the hair from her cheek, as if she could feel it across her skin. One hand was under her, the other outstretched, and as he looked more closely he could see there was something held inside it, something very small. Had she clutched at her murderer the last moment before he pushed her over, and torn something from him?

  Runcorn and the constable were still absorbed in conversation, facing each other. Monk put out one finger and moved Katrina’s hand very slightly, just enough for the object to slip out of the slack grasp and fall onto the stones. It was a button, a man’s coat button. He drew in his breath to tell Runcorn, then a wave of heat engulfed him, bringing the sweat out on his skin, and the instant after he was cold. It was his own button, the one she had torn off in a heated moment in the Botanic Gardens! But that had been hours ago!

  “What have you got?” Runcorn’s voice broke into his daze of horror, shattering his indecision. He could do nothing now, certainly not hide it. With clumsy fingers he fastened the lower buttons on his jacket so the top would be closed as well, hiding the fact that a button was gone, seeming as if it were simply not done up. He rose to his feet, his legs trembling. “A button,” he said huskily. He cleared his throat. “There was a button in her hand.”

  Runcorn bent down and lifted it from the pavement, turning it over and over curiously.

  Monk held his breath. Please God, Runcorn would not notice that it was exactly like the ones on Monk’s coat! It was dark; he was half turned from the street lamp. He would leave as soon as he could.

  “Man’s coat button, by the look of it,” Runcorn observed. “Must have pulled it off as she struggled with him.” He put it in his own breast pocket. “Good piece of evidence.” He gave his attention to the constable again. “You talk to the people around here. See what you can find. Do we know who she was yet?”

  “No, sir,” the constable answered. “They seen ’er comin’ an’ goin’, but not to speak to, like. Seemed very respectable. A Miss Barker, or Marcus, or summink like that, but not sure.”

  To evade it was a pointless lie, and he would be caught in it sooner or later. “Harcus,” Monk said quietly. “Katrina Harcus.”

  Runcorn stared at him. “You know her?”

  “Yes. I was working on an investigation for her.” Now the die was cast, but he could not have hidden it, and neither should he want to. It was one coat button, easily enough explained. There might even be people in the gardens who had seen them and would recall the gesture in which she had accidentally ripped it off. “I can help,” he went on. Now that fierce anger overtook the initial shock, he wanted to. He wanted to be revenged for her, to find who had done this and see him punished. It was all he could do for her now. He had failed in everything else, but she had wanted revenge; he remembered very clearly the fury in her face. He could get at least that for her.

  Runcorn’s eyes were wide. He let out his breath slowly. “So you weren’t here by accident. I should have known. What would you be doing in Cuthbert Street at this hour of the evening?” It was a rhetorical question to which he expected no answer. “What was it, this case you were working on?” he asked. “Do you know who did this to her?”

  “No, I don’t know,” Monk replied. “But I’ve an idea, and I’ll damn well find out . . . and prove it! She was betrothed to a Michael Dalgarno, a senior employee of Baltimore and Sons, a railway company—”

  “Just a minute!” Runcorn interrupted him. “Wasn’t there a Nolan Baltimore murdered in Leather Lane just a few weeks ago? Is that some connection with this?”

  “None that I’ve been able to find,” Monk admitted. “Looks like Baltimore simply went to enjoy his pleasures and got involved in a fight that ended badly. Perhaps he didn’t pay enough, or more likely he was drunk and picked a quarrel.”

  “So what were you doing here?” Runcorn pressed.

  “Nothing to do with that,” Monk replied.

  “There’s no need to be secretive now, Monk. She’s dead, poor creature.” He glanced down at her. “The only help you can give her is to find out who killed her.”

  “I know that!” Monk retorted sharply. He steadied himself with an effort. “As I said, she was betrothed to Michael Dalgarno. She was concerned that there might be some fraud to do with the new line they are building between London and Derby.” He saw Runcorn’s start of interest. “Specifically to do with the purchase of land—”

  “And was there?” Runcorn cut across him eagerly.

  “None that I could find, and I looked very carefully.” Monk knew he sounded defensive. He felt it. If he had found the proof, Katrina might still be alive.

  Runcorn looked dubious. “If it were plain to see, others would have found it too.”

  “I know more about railways than most people,” Monk responded, then instantly felt vulnerable. He had told too much about himself, opened up areas where he was guessing, piecing bits together one at a time—and to Runcorn, of all people!

  Theirs was an uneasy truce; the old resentments were covered over, not gone.

  “Do you?” Runcorn said with surprise. “How’s that, then? Thought you were in finance before you joined up with us ordinary police.” His words were civil enough, even his tone, but Monk knew the envy of money, of self-assurance, of a life Runcorn had never had, with its social ease and elegance.

  “Because railways have to be financed,” he replied. “The last thing I did before leaving banking was a new railway line near Liverpool.”

  Runcorn was silent for a moment. Perhaps he heard the strain in Monk’s voice or caught something of his grief and his anger.

  “So you found no fraud,” he said at last. “Does that mean for sure that there wasn’t any?”

  “No,” Monk admitted. “It means that if it was there, then it was very well hidden indeed. But she was convinced it was . . . even more so the last time I met her than in the beginning.”

  “So she’d found something, even if you hadn’t!” Runcorn eyed him sideways. “Did she give you any idea what it was?”

  “No. But her whole conviction that there was something wrong arose from things she overheard in the Baltimore offices, or house. Being betrothed to Dalgarno gave her access to conversations I had not.”

  Runcorn grunted. “Then we’d better go in and find out what there is—except I daresay he took it with him! Probably why he killed her.” He started forward toward the house.

  Monk changed his mind about leaving and decided to accept it as an invitation to accompany Runcorn. He could not afford to refuse. He moved with alacrity to follow, catching up with him at the entrance and going in a step behind him.

  It was still early in the evening, but by now word had spread that a woman had fallen or been thrown off the roof and was lying dead in the street. Neighbors waited in shocked silence or hasty, whispered conversations with each other. The uniformed constables were questioning them all, one by one, for anything they might have noticed either tonight or earlier.

  Runcorn was shown up the stairs to Katrina’s apartments. Monk was close on his heels, as if he belonged, and no one challenged him.

  “Right!” Runcorn said as soon as they were inside and the door closed. The gas was burning as she must have left it, but the corners were still full of shadows. Monk was grateful for it, conscious of the missing button as if it had been a bloodstain.

  “Where’d she keep her papers, anything that would be likely to tell us about this railway?” Runcorn asked, looking about him.

  “I don’t know. I’ve never been here before,” Monk replied, turning away from the light.

  “I thought you said she employed you? And you were on your way here tonight. You told me.” There was challenge in Runcorn’s voice.

  “It was the first time I’d come here,” Monk explained. “She came to my office, or we met in the Royal Botanic Gardens.” It sounded odd even as he said it.

  “Why’s that?” Runcorn said curiously, skepticism in his eyes.

  “She was very careful of her reputation,” Monk answered. “She was betrothed to an ambitious man. She wanted to be entirely discreet about having hired me. I imagine she intended it to appear that we were social acquaintances.” He went to put his hands in his pockets, then realized it would alter the sit of his coat, perhaps showing the missing button, and changed his mind. “After the first time, we always met in public, and by chance. She walked in the gardens every day at the same time, and if I had anything to report I knew where to find her.”

  “Extremely careful,” Runcorn agreed. “Poor creature,” he added softly. “Maybe she knew then that this Dalgarno was dangerous.” He shook his head. “Funny what attracts some women to a man. I’ll never understand that. Well, we’d better get on with it. We’ll just have to search.”