"I'm Milsom," said the man in the doorway again.

His clothes were grimed and dusty, his collar limp and soiled. There were two days' growth of red-grey stubble on his big jaw, and he bore himself like a man who was faint from lack of sleep.

He walked unsteadily to the table and fell into a chair.

"Where is van Heerden?" asked Beale, but Milsom shook his head.

"I left him two hours ago, after a long and unprofitable talk on patriotism," he said, and laughed shortly. "At that time he was making his way back to his house in Southwark."

"Then he is in London—here in London!"

Milsom nodded.

"You won't find him," he said brusquely. "I tell you I've left him after a talk about certain patriotic misgivings on my part—look!"

He lifted his right hand, which hitherto he had kept concealed by his side, and Oliva shut her eyes and felt deathly sick.

"Right index digit and part of the phalanges shot away," said Milsom philosophically. "That was my trigger-finger—but he shot first. Give me a drink!"

They brought him a bottle of wine, and he drank it from a long tumbler in two great breathless gulps.

"You've closed the coast to him," he said, "you shut down your wires and cables, you're watching the roads, but he'll get his message through, if——"

"Then he hasn't cabled?" said Beale eagerly. "Milsom, this means liberty for you—liberty and comfort. Tell us the truth, man, help us hold off this horror that van Heerden is loosing on the world and there's no reward too great for you."

Milsom's eyes narrowed.

"It wasn't the hope of reward or hope of pardon that made me break with van Heerden," he said in his slow way. "You'd laugh yourself sick if I told you. It was—it was the knowledge that this country would be down and out; that the people who spoke my tongue and thought more or less as I thought should be under the foot of the Beast—fevered sentimentality! You don't believe that?"

"I believe it."

It was Oliva who spoke, and it appeared that this was the first time that Milsom had noticed her presence, for his eyes opened wider.

"You—oh, you believe it, do you?" and he nodded.

"But why is van Heerden waiting?" asked McNorton. "What is he waiting for?"

The big man rolled his head helplessly from side to side, and the hard cackle of his laughter was very trying to men whose nerves were raw and on edge.

"That's the fatal lunacy of it! I think it must be a national characteristic. You saw it in the war again and again—a wonderful plan brought to naught by some piece of over-cleverness on the part of the super-man."

A wild hope leapt to Beale's heart.

"Then it has failed! The rust has not answered——?"

But Milsom shook his head wearily.

"The rust is all that he thinks—and then some," he said. "No, it isn't that. It is in the work of organization where the hitch has occurred. You know something of the story. Van Heerden has agents in every country in the world. He has spent nearly a hundred thousand pounds in perfecting his working plans, and I'm willing to admit that they are wellnigh perfect. Such slight mistakes as sending men to South Africa and Australia where the crops are six months later than the European and American harvests may be forgiven, because the German thinks longitudinally, and north and south are the two points of the compass which he never bothers his head about. If the Germans had been a seafaring people they'd have discovered America before Columbus, but they would never have found the North Pole or rounded the Cape in a million years."

He paused, and they saw the flicker of a smile in his weary eyes.

"The whole scheme is under van Heerden's hand. At the word 'Go' thousands of his agents begin their work of destruction—but the word must come from him. He has so centralized his scheme that if he died suddenly without that word being uttered, the work of years would come to naught. I guess he is suspicious of everybody, including his new Government. For the best part of a year he has been arranging and planning. With the assistance of a girl, a compatriot of his, he has reduced all things to order. In every country is a principal agent who possesses a copy of a simple code. At the proper moment van Heerden would cable a word which meant 'Get busy' or 'Hold off until you hear from me,' or 'Abandon scheme for this year and collect cultures.' I happen to be word-perfect in the meanings of the code words because van Heerden has so often drummed them into me."

"What are the code words?"

"I'm coming to that," nodded Milsom. "Van Heerden is the type of scientist that never trusts his memory. You find that kind in all the school—they usually spend their time making the most complete and detailed notes, and their studies are packed with memoranda. Yet he had a wonderful memory for the commonplace things—for example, in the plain English of his three messages he was word perfect. He could tell you off-hand the names and addresses of all his agents. But when it came to scientific data his mind was a blank until he consulted his authorities. It seemed that once he made a note his mind was incapable of retaining the information he had committed to paper. That, as I say, is a phenomenon which is not infrequently met with amongst men of science."

"And he had committed the code to paper?" asked Kitson.

"I am coming to that. After the fire at the Paddington works, van Heerden said the time had come to make a get away. He was going to the Continent, I was to sail for Canada. 'Before you go,' he said, 'I will give you the code—but I am afraid that I cannot do that until after ten o'clock.'"

McNorton was scribbling notes in shorthand and carefully circled the hour.

"We went back to his flat and had breakfast together—it was then about five o'clock. He packed a few things and I particularly noticed that he looked very carefully at the interior of a little grip which he had brought the previous night from Staines. He was so furtive, carrying the bag to the light of the window, that I supposed he was consulting his code, and I wondered why he should defer giving me the information until ten o'clock. Anyway, I could swear he took something from the bag and slipped it into his pocket. We left the flat soon after and drove to a railway station where the baggage was left. Van Heerden had given me bank-notes for a thousand pounds in case we should be separated, and I went on to the house in South London. You needn't ask me where it is because van Heerden is not there."

He gulped again at the wine.

"At eleven o'clock van Heerden came back," resumed Milsom, "and if ever a man was panic-stricken it was he—the long and the short of it is that the code was mislaid."

"Mislaid!" Beale was staggered.

Here was farce interpolated into tragedy—the most grotesque, the most unbelievable farce.

"Mislaid," said Milsom. "He did not say as much, but I gathered from the few disjointed words he flung at me that the code was not irredeemably lost; in fact, I have reason to believe that he knows where it is. It was after that that van Heerden started in to do some tall cursing of me, my country, my decadent race and the like. Things have been strained all the afternoon. To-night they reached a climax. He wanted me to help him in a burglary—and burglary is not my forte."

"What did he want to burgle?" asked McNorton, with professional interest.

"Ah! There you have me! It was the question I asked and he refused to answer. I was to put myself in his hands and there was to be some shooting if, as he thought likely, a caretaker was left on the premises to be entered. I told him flat—we were sitting on Wandsworth Common at the time—that he could leave me out, and that is where we became mutually offensive."

He looked at his maimed hand.

"I dressed it roughly at a chemist's. The iodine open dressing isn't beautiful, but it is antiseptic. He shot to kill, too, there's no doubt about that. A very perfect little gentleman!"

"He's in London?" said McNorton. "That simplifies matters."

"To my mind it complicates rather than simplifies," said Beale. "London is a vast proposition. Can you give us any idea as to the hour the burglary was planned for?"

"Eleven," said Milsom promptly, "that is to say, in a little over an hour's time."

"And you have no idea of the locality?"

"Somewhere in the East of London. We were to have met at Aldgate."

"I don't understand it," said McNorton. "Do you suggest that the code is in the hands of somebody who is not willing to part with it? And now that he no longer needs it for you, is there any reason why he should wait?"

"Every reason," replied Milsom, and Stanford Beale nodded in agreement. "It was not only for me he wanted it. He as good as told me that unless he recovered it he would be unable to communicate with his men."

"What do you think he'll do?"

"He'll get Bridgers to assist him. Bridgers is a pretty sore man, and the doctor knows just where he can find him."

As Oliva listened an idea slowly dawned in her mind that she might supply a solution to the mystery of the missing code. It was a wildly improbable theory she held, but even so slender a possibility was not to be discarded. She slipped from the group and went back to her room. For the accommodation of his ward, James Kitson had taken the adjoining suite to his own and had secured a lady's maid from an agency for the girl's service. She passed through the sitting-room to her own bedroom, and found the maid putting the room ready for the night.

"Minnie," she said, throwing a quick glance about the apartment, "where did you put the clothes I took off when I came?"

"Here, miss."

The girl opened the wardrobe and Oliva made a hurried search.

"Did you find—anything, a little ticket?"

The girl smiled.

"Oh yes, miss. It was in your stocking."

Oliva laughed.

"I suppose you thought it was rather queer, finding that sort of thing in a girl's stocking," she asked, but the maid was busily opening the drawers of the dressing-table in search of something.

"Here it is, miss."

She held a small square ticket in her hand and held it with such disapproving primness that Oliva nearly laughed.

"I found it in your stocking, miss," she said again.

"Quite right," said Oliva coolly, "that's where I put it. I always carry my pawn tickets in my stocking."

The admirable Minnie sniffed.

"I suppose you have never seen such a thing," smiled Oliva, "and you hardly knew what it was."

The lady's maid turned very red. She had unfortunately seen many such certificates of penury, but all that was part of her private life, and she had been shocked beyond measure to be confronted with this too-familiar evidence of impecuniosity in the home of a lady who represented to her an assured income and comfortable pickings.

Oliva went back to her sitting-room and debated the matter. It was a sense of diffidence, the fear of making herself ridiculous, which arrested her. Otherwise she might have flown into the room, declaimed her preposterous theories and leave these clever men to work out the details. She opened the door and with the ticket clenched in her hand stepped into the room.

If they had missed her after she had left nobody saw her return. They were sitting in a group about the table, firing questions at the big unshaven man who had made such a dramatic entrance to the conference and who, with a long cigar in the corner of his mouth, was answering readily and fluently.

But faced with the tangible workings of criminal investigation her resolution and her theories shrank to vanishing-point. She clasped the ticket in her hand and felt for a pocket, but the dressmaker had not provided her with that useful appendage.

So she turned and went softly back to her room, praying that she would not be noticed. She closed the door gently behind her and turned to meet a well-valeted man in evening-dress who was standing in the middle of the room, a light overcoat thrown over his arm, his silk hat tilted back from his forehead, a picture of calm assurance.

"Don't move," said van Heerden, "and don't scream. And be good enough to hand over the pawn ticket you are holding in your hand."

Silently she obeyed, and as she handed the little pasteboard across the table which separated them she looked past him to the bookshelf behind his head, and particularly to a new volume which bore the name of Stanford Beale.