Beatrice hoped that the plant might not be a beautiful one, but if it were she would have to sacrifice it, for it would be impossible to live in its neighbourhood and breathe that sickly sweet smell for long. In another moment or two she would know for herself. She advanced along the corridor quickly with the intention of turning up the lights and finding the offending flower. She knew her way perfectly well in the dark. She could have placed her hands upon the switches blindfold. Suddenly she stopped.

For the corridor was no longer in darkness. Some ten or fifteen yards ahead of her in the centre of the floor and on the thick pile of the Persian carpet was a round nebulous trembling orb of flickering blue flame. The rays rose and fell just as a fire does in a dark room, and for the moment Beatrice thought the boards were on fire.

But the peculiar dead-blue of the flame and its round shape did not fit in with this theory. The fire was apparently feeding upon nothing, and as Beatrice stood there fascinated she saw it roll a yard or two like a ball. It moved just as if a sudden draught had caught it—this strange will-o'-the-wisp at large in a country house. Beatrice shivered with apprehension wondering what was going to happen next. She could not move, she could not call out, for she was now past words. She could only watch and wait developments, her heart beating fast.

And developments came. For the best part of a yard a fairly strong glow surrounded the sobbing blue flame. Out of the glow came a long, thin, brown hand and arm, the slim fingers grasping a small brass pot and holding it over the flame. Almost immediately a dusty film rose from the pot and once again that sickly sweet perfume filled the corridor. Beatrice swayed before it, her senses soothed, her nerves numbed, until it seemed to her that she was falling backwards to the ground. A pair of arms caught her and she was lifted from the floor and carried swiftly along to her own room. It was all like a dream, from which she emerged by and by, to find herself safe and sound and the door of her room closed. She shook off the fears that held her in a grip of iron and laid her hand on the door knob. The lock was fastened on the outside.

What did it mean? What terrible things were happening on the other side of that locked door? It was useless to cry for help, for the walls were thick and no one slept in the same corridor but herself. All the servants had gone to bed long ago. Therefore, to ring the bell for help would be useless. All Beatrice could do was to wait and hope for assistance, and pray that this blue terror overhanging the house was not destined to end in tragedy. Perhaps this was an ingenious method by which modern thieves rifled houses with impunity and got away with their plunder before alarm could be raised. It seemed feasible, especially as she recollected that her dog had not challenged the intruders. She hoped nothing had happened to the terrier. She could not forget her tiny favourite even at this alarming moment.

Meanwhile, help was near at hand, as Beatrice expected. In the billiard-room Wilfrid Mercer had come to his senses, and made a dash for the window. He knew now that some dire catastrophe was at hand. He did not doubt that this was the work of the two strangers whom he had seen under the trees. In fact, with the scent burning and stinging in his nostrils there was no room for question. Whether the stuff was fatal or not he did not know and there was no time to ask. The thing to do was to create a powerful current throughout the house and clear the rooms and passages.

He thought of many things in that swift moment. His mind went flashing back to the time when he had encountered the dead Englishman in the Borneo hut with that knotted skein about his forehead. He thought about the strange discovery in the afternoon when those five knots had so mysteriously appeared again. He thought most of all of Beatrice and wondered if she were safe. All this shot through his mind in the passing of a second between the time he rose from his chair and fumbled for the catch of the windows opening on to the lawn. He had his handkerchief pressed tightly to his face. He dared not breathe yet. His heart was beating like a drum.

But the catch yielded at last. One after the other the windows were thrown wide and a great rush of air swept into the room causing the plants to dance and sway and the masses of ferns to nod their heads complainingly. It was good to feel the pure air of heaven again, to fill the lungs with a deep breath, and note the action of the heart growing normal once more. The thing had passed as rapidly as it had come and Wilfrid felt ripe for action. He was bold enough to meet the terror in whatever way it lifted up its head. As he turned towards the hall Cotter staggered into the room. His face was white and he shook like a reed in the wind. His fat hands were rubbing nervously together and he was the very embodiment of grotesque, almost ludicrous, fright.

"After all these years," he muttered, "after all these years. I am a wicked old man, sir, a miserable old wretch who doesn't deserve to live. And yet I always knew it would come. I knew it well enough though Mr. Flower always said we had got the better of those people. But I never believed it, sir, I never believed it. And now when I have worked and toiled and slaved to enjoy myself in my old age I am going to die like this. But it wasn't my fault, sir. I didn't do it. It was Flower. And if I had only known what was going to happen I would have cut my right hand off rather than have gone to Borneo ten years ago."

"In the name of common sense, what are you jabbering about?" Wilfrid said impatiently.