Perhaps two hours passed, perhaps three, when John Gilmer, sitting up in bed with a start, wide-awake and frightened, knew that someone was moving about in one of the three rooms that lay between him and his brother. He had absolutely no idea why he should have been frightened, for there was no dream or nightmare-memory that he brought over from unconsciousness, and yet he realized plainly that the fear he felt was by no means a foolish and unreasoning fear. It had a cause and a reason. Also—which made it worse—it was fully warranted. Something in his sleep, forgotten in the instant of waking, had happened that set every nerve in his body on the watch. He was positive only of two things—first, that it was the entrance of this person, moving so quietly there in the flat, that sent the chills down his spine; and, secondly, that this person was not his brother William.

John Gilmer was a timid man. The sight of a burglar, his eyes black-masked, suddenly confronting him in the passage, would most likely have deprived him of all power of decision—until the burglar had either shot him or escaped. But on this occasion some instinct told him that it was no burglar, and that the acute distress he experienced was not due to any message of ordinary physical fear. The thing that had gained access to his flat while he slept had first come—he felt sure of it—into his room, and had passed very close to his own bed, before going on. It had then doubtless gone to his brother’s room, visiting them both stealthily to make sure they slept. And its mere passage through his room had been enough to wake him and set these drops of cold perspiration upon his skin. For it was—he felt it in every fibre of his body—something hostile.

The thought that it might at that very moment be in the room of his brother, however, brought him to his feet on the cold floor, and set him moving with all the determination he could summon towards the door. He looked cautiously down an utterly dark passage; then crept on tiptoe along it. On the wall were old-fashioned weapons that had belonged to his father; and feeling a curved, sheathless sword that had come from some Turkish campaign of years gone by, his fingers closed tightly round it, and lifted it silently from the three hooks whereon it lay. He passed the doors of the bathroom and dining-room, making instinctively for the big sitting-room where the violins were kept in their glass cases. The cold nipped him. His eyes smarted with the effort to see in the darkness. Outside the closed door he hesitated.

Putting his ear to the crack, he listened. From within came a faint sound of someone moving. The same instant there rose the sharp, delicate “ping” of a violin-string being plucked; and John Gilmer, with nerves that shook like the vibrations of that very string, opened the door wide with a fling and turned on the light at the same moment. The plucked string still echoed faintly in the air.

The sensation that met him on the threshold was the well-known one that things had been going on in the room which his unexpected arrival had that instant put a stop to. A second earlier and he would have discovered it all in the act. The atmosphere still held the feeling of rushing, silent movement with which the things had raced back to their normal, motionless positions. The immobility of the furniture was a mere attitude hurriedly assumed, and the moment his back was turned the whole business, whatever it might be, would begin again. With this presentment of the room, however—a purely imaginative one—came another, swiftly on its heels.

For one of the objects, less swift than the rest, had not quite regained its “attitude” of repose. It still moved. Below the window curtains on the right, not far from the shelf that bore the violins in their glass cases, he made it out, slowly gliding along the floor. Then, even as his eye caught it, it came to rest.

And, while the cold perspiration broke out all over him afresh, he knew that this still moving item was the cause both of his waking and of his terror. This was the disturbance whose presence he had divined in the flat without actual hearing, and whose passage through his room, while he yet slept, had touched every nerve in his body as with ice. Clutching his Turkish sword tightly, he drew back with the utmost caution against the wall and watched, for the singular impression came to him that the movement was not that of a human being crouching, but rather of something that pertained to the animal world. He remembered, flash-like, the movements of reptiles, the stealth of the larger felines, the undulating glide of great snakes. For the moment, however, it did not move, and they faced one another.

The other side of the room was but dimly lighted, and the noise he made clicking up another electric lamp brought the thing flying forward again—towards himself. At such a moment it seemed absurd to think of so small a detail, but he remembered his bare feet, and, genuinely frightened, he leaped upon a chair and swished with his sword through the air about him. From this better point of view, with the increased light to aid him, he then saw two things—first, that the glass case usually covering the Guarnerius violin had been shifted; and, secondly, that the moving object was slowly elongating itself into an upright position. Semi-erect, yet most oddly, too, like a creature on its hind legs, it was coming swiftly towards him. It was making for the door—and escape.

The confusion of ghostly fear was somehow upon him so that he was too bewildered to see clearly, but he had sufficient self-control, it seemed, to recover a certain power of action; for the moment the advancing figure was near enough for him to strike, that curved scimitar flashed and whirred about him, with such misdirected violence, however, that he not only failed to strike it even once, but at the same time lost his balance and fell forward from the chair whereon he perched—straight into it.

And then came the most curious thing of all, for as he dropped, the figure also dropped, stooped low down, crouched, dwindled amazingly in size, and rushed past him close to the ground like an animal on all fours. John Gilmer screamed, for he could no longer contain himself. Stumbling over the chair as he turned to follow, cutting and slashing wildly with his sword, he saw halfway down the darkened corridor beyond the scuttling outline of, apparently, an enormous—cat!