“What was it?”

“I heard a sort of scratching at an upper window.  It was just like—­”

“Yes!  Yes!”

“Like a great cat trying to gain admittance!”

“See that all the doors and windows are fastened!” I cried.  “Whatever happens or whoever knocks don’t open to any one, you understand?  We will be with you in less than half an hour!”

Still in that frightened voice: 

“For heaven’s sake,” she begged, “don’t be long, Jack!...”

I became aware of a singular rasping sound on the wires, which rendered Isobel’s words almost unintelligible.  Then: 

“Jack,” I heard, in a faint whisper, “there is a strange noise ... just outside the room....”

Silence came.  But, vaguely, above that rasping sound, I had detected the words:  “Cutting ... telephone ... wires....”

I replaced the receiver.  My hand was shaking wildly.

“Gatton!” I said, “do you understand? It has turned its attention to Miss Merlin!” Then, raising my voice:  “Coates!” I cried, “Coates! run for the car!  Hurry, man!  Some one’s life depends on your speed!”

Inspector Gatton grabbed the telephone directory.

“I will instruct the local police,” he muttered.  “Give me the exact address, Mr. Addison, and go and see the cab that’s outside.  If it’s a good one we’ll take it instead of waiting.”

Out I dashed, spurred by a sickly terror, crying Mrs. Wentworth’s address as I ran.  And of the ensuing five minutes I retain nothing but chaotic memories:  the bewildered cabman; the police bending over the gaunt form on my study floor; Gatton’s voice shouting orders.  Then, we had jumped into the cab and enjoining the man to drive like fury, were speeding off through the busy London streets.  Leaving the quietude of one suburb for the maelstrom of central London, we presently emerged into an equally quiet backwater upon the Northerly outskirts.

It was a nightmare journey, but when at last we approached the house for which we were bound my apprehension and excitement grew even keener.  It was infinitely more isolated and lonely than I had ever realized, behind its high brick walls.

Of the local police there was no sign.  And without hesitation we ran in at the open gate and up the path towards the porch.  Every window in the house was brightly illuminated, testifying to the greatness of the occupant’s fear.  Gaining the porch, we stopped, as if prompted by some mutual thought, and listened.

There was the remote murmuring of busy London, but here surrounding us was a stillness as great as that which prevailed in my own neighborhood; and as we stood there, keenly alert—­distinctly we both heard the howling of dogs!

“You hear it?” rapped Gatton.

“I do!” I replied.

Grasping the bell-knob, I executed a vigorous peal upon the bell.  There was a light in the hallway but my ringing elicited no response, until: