Unknown to those who had taken part in the conference at Viner's house, unknown even to Carless, who in the multiplicity of his engagements, had forgotten the instructions which he had given on the previous afternoon to Portlethwaite, a strict watch was being kept on the man around whom all the events of that morning had centred. Portlethwaite, after Methley and his client had left Carless and Driver's office, had given certain instructions to one of his fellow-clerks, a man named Millwaters, in whose prowess as a spy he had unlimited belief. Millwaters was a fellow of experience. He possessed all the qualities of a sleuth-hound and was not easily baffled in difficult adventures. In his time he had watched erring husbands and doubtful wives; he had followed more than one high-placed wrong-doer running away from the consequences of forgery or embezzlement; he had conducted secret investigations into the behaviour of persons about whom his employers wanted to know something. In person and appearance he was eminently fitted for his job—a little, inconspicuous, plain-featured man who contrived to look as if he never saw anything. And to him, knowing that he was to be thoroughly depended upon, Portlethwaite had given precise orders.

"You'll go up to Lancaster Gate tonight, Millwaters, and get a good look at that chap," Portlethwaite had told him. "Take plenty of money—I'll speak to the cashier about that—and be prepared for anything, even to following, if he bolts. Once you've seen him, you're not to lose sight of him; make sure of him last thing today and first thing tomorrow. Follow him wherever he goes, make a note of wherever he goes, and particularly of whoever he meets. And if there's need, ring me up here, and let's know what's happening, or if you want assistance."

There was no need for Millwaters to promise faithful compliance; Portlethwaite knew well enough that to put him on a trail was equivalent to putting a hound on the scent of a fox or a terrier to the run of a rat. And that evening, Millwaters, who had clever ways of his own, made himself well acquainted with the so-called Mr. Cave's appearance, and assured himself that his man had gone peacefully to rest at his hotel, and he had seen him again before breakfast next morning and had been in quiet and unobtrusive attendance upon him when, later, he visited Methley's office and subsequently walked away with Methley to the police-court. And Millwaters was in the police-court, meditatively sucking peppermint lozenges in a corner, when Mr. Cave was unexpectedly asked to give evidence; he was there, too, until Mr. Cave left the court.

Cave's remarkable story ran off Millwaters' mentality like raindrops off a steep roof. It mattered nothing to him. He did not care the value of a brass button if Cave was Earl of Ellingham or Duke of Ditchmoor; his job was to keep his eye on him, whoever he was. And so when Viner and his party went round to Markendale Square, Millwaters slunk along in their rear, and at a corner of the Square he remained, lounging about, until his quarry reappeared. Two or three of the other men came out with Cave, but Millwaters noticed that Cave immediately separated from them. He was evidently impressing upon them that he was in a great hurry about something or other, and sped away from them, Millwaters's cold eye upon him. And within a minute Millwaters had observed what seemed to him highly suspicious circumstance—Cave, on leaving the others, had shot off down a side-street in the direction of Lancaster Gate, but as soon as he was out of sight of Markendale Square, had doubled in his tracks, hurried down another turning and sped away as fast as he could walk towards Paddington Station.

Millwaters, shorter in the leg than the tall man in front, had to hurry to keep him in sight, but he was never far behind as Cave hastened along Craven Road and made for the terminus. Once or twice in this chase the quarry lifted a hand to an approaching taxicab, only to find each was engaged; it was not until he and his pursuer were in front of the Great Western Hotel that Cave found an empty cab, hailed it, and sprang in. Millwaters grinned quietly at that; he was used to this sort of chase, and he had memorized car and number before Cave had been driven off. It was a mere detail to charter the next, and to give a quiet word and wink to its chauffeur, who was opening its door for Millwaters when a third person came gently alongside and tapped the clerk's shoulder. Millwaters turned sharply and encountered Mr. Perkwite's shrewd eyes.

"All right, Millwaters!" said the barrister. "I know what you're after!
I'm after the same bird. We'll go together."

Millwaters knew Mr. Perkwite very well as a promising young barrister whom Carless and Driver sometimes favoured with briefs. Mr. Perkwite's presence did not disturb him; he moved into the farther corner, and Mr. Perkwite slipped inside. The car moved off in pursuit of the one in front.

"So you're on that game, Mr. Perkwite?" remarked Millwaters. "Ah! And who might have got you on to it, if one may ask?"

"You know that I was at your people's office yesterday?" said Perkwite.

"Saw you there," replied Millwaters.

"It was about this business," said the barrister. "Did you see me in the police-court this morning?"

"I did—listening for all you were worth," answered the clerk.

"And I dare say you saw me go with the rest of them to Mr. Viner's, in
Markendale Square?" said Perkwite.

"Right again, sir," assented Millwaters. "I did."

"This fellow in front," observed Perkwite, "made some statements at Viner's, in answer to your principal, Mr. Carless, which incline me to the opinion that he's an impostor in spite of his carefully concocted stories."

"Shouldn't wonder, Mr. Perkwite." said Millwaters. "But that's not my business. My job is to keep him under observation."

"That's what I set out to do when I came out of Viner's," said the barrister. "He's up to something. He assured us as we left the house that he'd a most pressing engagement at his hotel in Lancaster Gate; the next minute, happening to glance down a side-street, I saw him cutting off in the direction of Paddington. And now he's evidently making for the City."

"Well, I'm after him," remarked Millwaters. He leaned out of his window, called the chauffeur, and gave him some further instructions. "Intelligent chap, this, Mr. Perkwite," he said as he sat down again. "He understands—some of 'em are poor hands at this sort of game."

"You're a pretty good hand yourself, I think?" suggested the barrister, with a smile.

"Ought to be," said Millwaters. "Had plenty of experience, anyway."

It seemed to Perkwite that his companion kept no particular observation on the car in front as it sped along to and through the northern edge of the City and beyond. But Millwaters woke to action as their own car progressed up Whitechapel Road, and suddenly he gave a warning word to the barrister and a smart tap on the window behind their driver. The car came to a halt by the curb; and Millwaters, slipping out, pushed some money into the man's hand and drew Perkwite amongst the people who were crowding the sidewalk. The barrister looked in front and around and seemed at a loss.

"Where is he?" he asked. "Hang it, I've lost him!"

"I haven't!" said Millwaters. "He left his car before we left ours. Our man knew what he was after—he slowed up and passed him until I saw where he went." He twisted Perkwite round and pointed to the mouth of a street which they had just passed.

"He's gone down there," he said. "Nice neighbourhood, too! I know something of it. Now, Mr. Perkwite, if you please, we'll separate. You take the right of that street—I'll take the left. Keep a look out for my gentleman's Homburg hat—grey, with a black band—and keep the tail of your eye on me, too."

Cave's headgear was easily followed down the squalid street. Its owner went swiftly ahead, with Millwaters in pursuit on one pavement, and the barrister on the other, until he finally turned into a narrower and shabbier thoroughfare. Then the clerk hurried across the road, attracted Perkwite's attention, winked at him as he passed without checking his pace, and whispered two or three words.

"Wait—by the street-corner!"

Perkwite pulled up, and Millwaters went down the dismal street in pursuit of the Homburg hat. This excellent indication of its owner's presence suddenly vanished from Perkwite's sight, and presently Millwaters came back.

"Ran him to earth—for the time being, anyway," he said. "He's gone into a surgery down there—a Dr. Martincole's. Number 23—brass plate on door—next to a drug-shop. Suspicious sort of spot, altogether."

"Well?" demanded Perkwite. "What next? You know best, Millwaters."

The clerk jerked a thumb down the side of the dismal street on which they were standing.

"There's a public-house down there," he said, "almost opposite this surgery. Fairly decent place for this neighbourhood—bar-parlour looking out on the street. Better slip in there and look quietly out. But remember, Mr. Perkwite—don't seem to be watching anything. We're just going in for a bottle of ale, and talking business together.

"Whatever you recommend," said Perkwite.

He followed his companion down the street to the tavern, a joyless and shabby place, the bar-parlour of which, a dark and smoke-stained room was just then empty, and looked over its torn half-blind across the way.

"Certainly a queer place for a man who professes to be a peer of the realm to visit!" he muttered. "Well, now, what do you propose to do, Millwaters?"

"Hang about here and watch," whispered the clerk. "Look out!"

A face, heavy and bloated, appeared at a hatch-window at the back of the room, and a gruff voice made itself heard.

"Any orders, gents?"

"Two bottles o' Bass, gov'nor," responded Millwaters promptly, dropping into colloquial Cockney speech. He turned to Perkwite and winked. "Well, an' wot abaht this 'ere bit o' business as I've come rahnd abaht, Mister?" he went on, nudging his companion, in free-and-easy style.

"Yer see, it's this ere wy wiv us—if yer can let us have that there stuff reasonable, d'yer see—" He drew Perkwite over to the window and began to whisper, "That'll satisfy him," he said with a sharp glance at the little room behind the hatch where the landlord was drawing corks. "He'll think we're doing a bit of trade, so we've nothing to do but stand in this window and keep an eye on the street. Out of this I'm not going till I see whether that fellow comes out or stops in!"

Some time had passed, and Millwaters had been obliged to repeat his order for bottled Bass before anything took place in the street outside. Suddenly he touched his companion's elbow.

"Here's a taxicab coming along and slowing up for somewhere about here," he whispered. "And—Lord, if there aren't two ladies in it—in a spot like this! And—whew!" he went on excitedly. "Do you see 'em, Mr. Perkwite? The young un's Miss Wickham, who came to our office about this Ashton affair. I don't know who the old un is—but she evidently knows her way."

The berry-faced landlord had now shut down the hatch, and his two bar-parlour customers were alone and unobserved. Perkwite drew away from the window, pulling Millwaters by the sleeve.

"Careful!" he said. "There's something seriously wrong here, Millwaters! What's Miss Wickham being brought down here for? See, they've gone into that surgery, and the car's going off. Look here—we've got to do something, and at once!"

But Millwaters shook his head.

"Not my job, Mr. Perkwite!" he answered. "My business is with the man—Cave! I've nothing to do with Miss Wickham, sir, nor with the old lady that's taken her in there. Cave's my mark! Queer that the young lady's gone there, no doubt, but—no affair of mine."

"It's going to be an affair of mine, then," said Perkwite. "I'm going off to the police!"

Millwaters put out a detaining hand.

"Don't, Mr. Perkwite!" he said. "To get police into a quarter like this is as bad as putting a light to dry straw. I'll tell you a better plan than that, sir—find the nearest telephone-box and call up our people—call Mr. Carless, tell him what you've seen and get him to come down and bring somebody with him. That'll be far better than calling the police in."

"Give me your telephone-number, then," said Perkwite, "and keep a strict watch while I'm away."

Millwaters repeated some figures and a letter, and Perkwite ran off up the street and toward the Whitechapel Road, anxiously seeking for a telephone booth. It was not until he had got into the main thoroughfare that he found one; he then had some slight delay in getting in communication with Carless and Driver's office; twenty minutes had elapsed by the time he got back to the dismal street. At its corner he encountered Millwaters, lounging about hands in pockets. Millwaters wagged his head.

"Here's another queer go!" he said. "There's been another arrival at
Number 23—not five minutes since. Another of our little lot!"

"Who?" demanded Perkwite.

"Viner!" replied Millwaters. "Came peeping and perking along the street, took a glimpse of the premises and the adjacent purlieus, rang at Number 23, and was let in by—the party that came with Miss Wickham! Now, whatever can he be doing there, Mr. Perkwite?"

"Whatever can any of them be doing there!" muttered Perkwite. "Viner! What business can he have in this place? It seems—by George, Millwaters," he suddenly exclaimed, "what if this is some infernal plant—trap—something of that sort? Do you know, in spite of what you say, I really think we ought to get hold of the nearest police and tell them—"

"Wait, Mr. Perkwite!" counselled Millwaters. "Our governor is a pretty cute and smart sort, and he's vastly interested in this Miss Wickham; so Portlethwaite and he'll be on their way down here now, hot foot; and with help, too, if he thinks she's in any danger. Now, he can go straight to that door and demand to see her, and—"

"Why can't we?" interrupted Perkwite. "I'd do it! Lord, man, she may be in real peril—"

"Not while Viner's in there," said Millwaters quietly. "I might possibly have gone and rung the bell myself, but for that. But Viner's in there—wait!"

And Perkwite waited, chafing, at the corner of the dismal street, until a quarter of an hour had passed. Then a car came hurrying along and pulled up as Millwaters and his companion were reached, and from it sprang Mr. Carless, Lord Ellingham and two men in plain-clothes, at the sight of whom Perkwite heaved a huge sigh of intense relief.