It vanished instantly, into measureless black silence.

"Now you've jolly well done it, haven't you!"' the Rangar laughed in his ear. "That was her blue light—Yasmini's!"

It was a minute before King answered, for both animals were all but frantic with their sense of their riders' state of mind; it needed horsemanship to get them back under control.

"How do you know whose light it was?" King demanded, when the horse and mare were head to head again.

"It was prearranged. She promised me a signal at the point where I am to leave the track!"

"Where's that guide?" demanded King; and Darya Khan came forward out of the night, with his rifle cocked and ready.

"Did she not say Khinjan is the destination?"'

"Aye!" the fellow answered.

"I know the way to Khinjan. That is not it. Get down there and find out what that light was. Shout back what you find!"

The man obeyed instantly and sprang down into darkness. But King had hardly given the order when shame told him he had sent a native on an errand he had no liking for himself.

"Come back!" he shouted. "I'll go."

But the man had gone, slipping noiselessly in the dark from rock to rock.

So King drove both spurs home, and set his unwilling horse to scrambling downward at an angle he could not guess, into blackness he could feel, trusting the animal to find a footing where his own eyes could make out nothing.

To his disgust he heard the Rangar follow immediately. To his even greater disgust the black mare overtook him. And even then, with his own mount stumbling and nearly pitching him headforemost at each lurch, he was forced to admire the mare's goatlike agility, for she descended into the gorge in running leaps, never setting a wrong foot. When he and his horse reached the bottom at last he found the Rangar waiting for him.

"This way, sahib!"

The next he knew sparks from the black mare's heels were kicking up in front of him, and a wild ride had begun such as he had never yet dreamed of. There was no catching up, for the black mare could gallop two to his horse's one; but he set his teeth and followed into solid night, trusting ear, eye, guesswork and the God of Secret Service men who loves the reckless.

Once in a minute or so he would see a spark, or a shower of them, where the mare took a turn in a hurry. Once in every two or three minutes he caught sight for a second of the same blue siren light that had started the race. He suspected that there were many torches placed at intervals. It could not be one man running. More than once it occurred to him to draw and shoot, but that thought died into the darkness whence it came. Never once while he rode did he forget to admire the Rangar's courage or the black mare's speed.

His own horse developed a speed and stamina he had not suspected, and probably the Rangar did not dare extend the mare to her limit in the dark; at all events, for ten, perhaps fifteen, minutes of breathless galloping he almost made a race of it, keeping the Rangar, either within sight or sound.

But then the mare swerved suddenly behind a boulder and was gone. He spurred round the same great rock a minute later, and was faced by a blank wall of shale that brought his horse up all standing. It led steep up for a thousand feet to the sky-line. There was not so much as a goat-track to show in which direction the mare had gone, nor a sound of any kind to guide him.

He dismounted and stumbled about on foot for about ten minutes with his eyes two feet from the earth, trying to find some trace of hoof. Then he listened, with his ear to the ground. There was no result.

He knew better than to shout, for that would sound like a cry of distress, and there is no mercy whatever in the "Hills" for lost wanderers, or for men who seem lost. He had not a doubt there were men with long jezails lurking not far away, to say nothing of those responsible for the blue torchlight.