THE train was late, and as our cab turned out of Waterloo Station and began to ascend to the bridge, from a hundred steeples rang out the gongs of midnight, the bell of St. Paul's raised above them all to vie with the deep voice of Big Ben.  
I looked out from the cab window across the river to where, towering above the Embankment, that place of a thousand tragedies, the light of some of London's greatest caravanserais formed a sort of minor constellation. From the subdued blaze that showed the public supper-rooms I looked up to the hundreds of starry points marking the private apartments of those giant inns.
 
I thought how each twinkling window denoted the presence of some bird of passage, some wanderer temporarily abiding in our midst. There, floor piled upon floor above the chattering throngs, were these less gregarious units, each something of a mystery to his fellow-guests, each in his separate cell; and each as remote from real human companionship as if that cell were fashioned, not in the bricks of London, but in the rocks of Hindustan!
 
In one of those rooms Graham Guthrie might at that moment be sleeping, all unaware that he would awake to the Call of Siva, to the summons of death. As we neared the Strand, Smith stopped the cab, discharging the man outside Sotheby's auction-rooms.
 
"One of the doctor's watch-dogs may be in the foyer," he said thoughtfully, "and it might spoil everything if we were seen to go to Guthrie's rooms. There must be a back entrance to the kitchens, and so on?"
 
"There is," I replied quickly. "I have seen the vans delivering there. But have we time?"
 
"Yes. Lead on."
 
We walked up the Strand and hurried westward. Into that narrow court, with its iron posts and descending steps, upon which opens a well-known wine-cellar, we turned. Then, going parallel with the Strand, but on the Embankment level, we ran round the back of the great hotel, and came to double doors which were open. An arc lamp illuminated the interior and a number of men were at work among the casks, crates and packages stacked about the place. We entered.
 
"Hallo!" cried a man in a white overall, "where d'you think you're going?"
 
Smith grasped him by the arm.
 
"I want to get to the public part of the hotel without being seen from the entrance hall," he said. "Will you please lead the way?"
 
"Here—" began the other, staring.
 
"Don't waste time!" snapped my friend, in that tone of authority which he knew so well how to assume. "It's a matter of life and death. Lead the way, I say!"
 
"Police, sir?" asked the man civilly.
 
"Yes," said Smith; "hurry!"
 
Off went our guide without further demur. Skirting sculleries, kitchens, laundries and engine-rooms, he led us through those mysterious labyrinths which have no existence for the guest above, but which contain the machinery that renders these modern khans the Aladdin's palaces they are. On a second-floor landing we met a man in a tweed suit, to whom our cicerone presented us.
 
"Glad I met you, sir. Two gentlemen from the police."
 
The man regarded us haughtily with a suspicious smile.
 
"Who are you?" he asked. "You're not from Scotland Yard, at any rate!"
 
Smith pulled out a card and thrust it into the speaker's hand.
 
"If you are the hotel detective," he said, "take us without delay to Mr. Graham Guthrie."
 
A marked change took place in the other's demeanor on glancing at the card in his hand.
 
"Excuse me, sir," he said deferentially, "but, of course, I didn't know who I was speaking to. We all have instructions to give you every assistance."
 
"Is Mr. Guthrie in his room?"
 
"He's been in his room for some time, sir. You will want to get there without being seen? This way. We can join the lift on the third floor."
 
Off we went again, with our new guide. In the lift:
 
"Have you noticed anything suspicious about the place to-night?" asked Smith.
 
"I have!" was the startling reply. "That accounts for your finding me where you did. My usual post is in the lobby. But about eleven o'clock, when the theater people began to come in I had a hazy sort of impression that someone or something slipped past in the crowd—something that had no business in the hotel."
 
We got out of the lift.
 
"I don't quite follow you," said Smith. "If you thought you saw something entering, you must have formed a more or less definite impression regarding it."
 
"That's the funny part of the business," answered the man doggedly. "I didn't! But as I stood at the top of the stairs I could have sworn that there was something crawling up behind a party—two ladies and two gentlemen."
 
"A dog, for instance?"
 
"It didn't strike me as being a dog, sir. Anyway, when the party passed me, there was nothing there. Mind you, whatever it was, it hadn't come in by the front. I have made inquiries everywhere, but without result." He stopped abruptly. "No. 189—Mr. Guthrie's door, sir."
 
Smith knocked.
 
"Hallo!" came a muffled voice; "what do you want?"
 
"Open the door! Don't delay; it is important."
 
He turned to the hotel detective.
 
"Stay right there where you can watch the stairs and the lift," he instructed; "and note everyone and everything that passes this door. But whatever you see or hear, do nothing without my orders."
 
The man moved off, and the door was opened. Smith whispered in my ear:
 
"Some creature of Dr. Fu-Manchu is in the hotel!"
 
Mr. Graham Guthrie, British resident in North Bhutan, was a big, thick-set man—gray-haired and florid, with widely opened eyes of the true fighting blue, a bristling mustache and prominent shaggy brows. Nayland Smith introduced himself tersely, proffering his card and an open letter.
 
"Those are my credentials, Mr. Guthrie," he said; "so no doubt you will realize that the business which brings me and my friend, Dr. Petrie, here at such an hour is of the first importance."
 
He switched off the light.
 
"There is no time for ceremony," he explained. "It is now twenty-five minutes past twelve. At half-past an attempt will be made upon your life!"
 
"Mr. Smith," said the other, who, arrayed in his pajamas, was seated on the edge of the bed, "you alarm me very greatly. I may mention that I was advised of your presence in England this morning."
 
"Do you know anything respecting the person called Fu-Manchu—Dr. Fu-Manchu?"
 
"Only what I was told to-day—that he is the agent of an advanced political group."
 
"It is opposed to his interests that you should return to Bhutan. A more gullible agent would be preferable. Therefore, unless you implicitly obey my instructions, you will never leave England!"
 
Graham Guthrie breathed quickly. I was growing more used to the gloom, and I could dimly discern him, his face turned towards Nayland Smith, whilst with his hand he clutched the bed-rail. Such a visit as ours, I think, must have shaken the nerve of any man.
 
"But, Mr. Smith," he said, "surely I am safe enough here! The place is full of American visitors at present, and I have had to be content with a room right at the top; so that the only danger I apprehend is that of fire."
 
"There is another danger," replied Smith. "The fact that you are at the top of the building enhances that danger. Do you recall anything of the mysterious epidemic which broke out in Rangoon in 1908—the deaths due to the Call of Siva?"
 
"I read of it in the Indian papers," said Guthrie uneasily. "Suicides, were they not?"
 
"No!" snapped Smith. "............