“My God, look!” cried Gatton.

He pulled me backward out of the porch, looking upward to the window of a room on the first floor.

A silhouette appeared there—­undoubtedly that of Isobel.  She seemed to be endeavoring to pull the curtain aside ... when the shadow of a long arm reached out to her, and she was plucked irresistibly back.  The sound of a muffled scream reached my ears, and: 

“Great heavens! It has got in!” whispered Gatton.

He raised his hand and the shrill note of a police whistle split the silence.

The closed door was obviously too strong to be forced without the aid of implements for the purpose, and we began to run around the house, looking for some means of entrance.  Suddenly: 

“There’s the way!” said Gatton, and pointed up to where the branches of an old elm tree stretched out before a window.  The glass of the window was entirely shattered except for some few points which glittered like daggers around the edges of the frame.

“Can you do it?”

“In the circumstances—­yes!” I said.

Without more ado I began to climb the elm, stimulated by memories of how I had entered Friar’s Park.  It afforded little foothold for the first six feet and proved an even tougher job than I had anticipated, but at last I reached a projecting limb, the bulk of which had been sawn off.  Gatton’s agility was not so great as mine, but at the moment that I half staggered and half fell into the room, I heard him swinging himself onto the limb behind me so that as I leaped to the open door he came tumbling in through the window, and the pair of us raced side by side along the corridor towards an apartment facing front from which horrifying cries and sounds of conflict now arose.

Gaining the closed door of this room, I literally hurled myself upon it.  It crashed open ... and I beheld a dreadful spectacle.

Isobel lay forced back upon a settee which occupied the window recess—­and bending over her, having her back turned towards me, was a tall, lithe, black-clad woman who, so far as I could see, was clutching Isobel’s throat and forcing her further backward—­backward upon the cushions strewn upon the settee!

But instant upon the door’s opening this horrible scene changed.  With never a backward glance (so that neither Gatton nor I had even a momentary glimpse of her face) the black-robed woman sprang to the window, opened it in a moment, and to my dismay and astonishment sprang out into the darkness!

My first thought was for Isobel—­but Gatton leaped across the room and craned out, peering on to the path below.  Indeed, even as I dropped on my knees beside the swooning girl, I found myself listening for the thud of the falling body upon the gravel path.  But no sound reached me.  That uncanny creature must have alighted truly in the manner of a cat.  Through the stillness of the house rang the flat note of a police-whistle.  From some distant spot I heard a faint reply.