We blundered up the steps, and in front of us I seemed to hear a sound of metal grating against metal. The stairs ended abruptly, on a landing that terminated in a blank wall. Gordon hammered against this and the inevitable secret doorway opened. Light streamed in, through the bars of a sort of grille. Men in the uniform of London police were sawing at these with hacksaws, and even as they greeted us, an opening was made through which we crawled. "You're hurt, sir!" One of the men took Gordon's arm. My companion shook him off. "There's no time to lose! Out of here, as quick as we can go!" I saw that we were in a basement of some sort. We hastened up the steps and out into the early dawn which was turning the east scarlet. Over the tops of smaller houses I saw in the distance a great gaunt building on the roof of which, I felt instinctively, that wild drama had been enacted the night before. "That building was leased some months ago by a mysterious Chinaman," said Gordon, following my gaze. "Office building originally--the neighborhood deteriorated and the building stood vacant for some time. The new tenant added several stories to it but left it apparently empty. Had my eye on it for some time." This was told in Gordon's jerky swift manner as we started hurriedly along the sidewalk. I listened mechanically, like a man in a trance. My vitality was ebbing fast and I knew that I was going to crumple at any moment. "The people living in the vicinity had been reporting strange sights and noises. The man who owned the basement we just left heard queer sounds emanating from the wall of the basement and called the police. About that time I was racing back and forth among those cursed corridors like a hunted rat and I heard the police banging on the wall. I found the secret door and opened it but found it barred by a grating. It was while I was telling the astounded policemen to procure a hacksaw that the pursuing negroes, whom I had eluded for the moment, came into sight and I was forced to shut the door and run for it again. By pure luck I found you and by pure luck managed to find the way back to the door. "Now we must get to Scotland Yard. If we strike swiftly, we may capture the entire band of devils. Whether I killed Kathulos or not I do not know, or if he can be killed by mortal weapons. But to the best of my knowledge all of them are now in those subterranean corridors and----" At that moment the world shook! A brain-shattering roar seemed to break the sky with its incredible detonation; houses tottered and crashed to ruins; a mighty pillar of smoke and flame burst from the earth and on its wings great masses of debris soared skyward. A black fog of smoke and dust and falling timbers enveloped the world, a prolonged thunder seemed to rumble up from the center of the earth as of walls and ceilings falling, and amid the uproar and the screaming I sank down and knew no more. _21. The Breaking of the Chain_