Without hesitation the three fired.  One of the dogs dropped dead; but the others, though wounded, came on.  One bounded at Muriel.  Frank threw himself in front of her, firing rapidly at it.  Several bullets struck it, but the savage brute sprang at his throat.  He grappled with it, striving by main strength to hold it off.  Muriel rushed to his aid and putting her pistol to the mastiff’s head shot it dead.  Tashi meantime had killed the third.

Knowing that their pursuers must be close behind the dogs they fled into the gorge.  On either hand stupendous cliffs towered up two thousand feet above them, scarcely a hundred yards apart, seeming to meet overhead and shut off the sky.  Here and there the giant walls were split from top to bottom in slits opening off the main passage.  As the fugitives ran on the gorge narrowed until it was scarcely fifty yards wide, and they began to fear that it might prove only a cul-de-sac in which they would be hopelessly trapped.  They heard cries behind them, strangely echoed by the rocky walls.  Breathless, panting, their tired limbs giving way under them, they staggered blindly on.

The pass turned sharply to the right.  As they approached the bend they became aware of a dull rumbling, and the ground, which suddenly began to slope steeply down, shook violently under their feet.  Wondering what new danger, what fresh horror, awaited them they stumbled on, turned the corner and stopped short in dismayed despair.

From side to side the gorge was filled with a tumultuous, racing flood of foam-flecked water, a rushing river that poured out of a natural tunnel in the steeply sloping rocky bottom of the pass as from a sluice.  It surged against the precipitous cliffs, leaping up against the walls that hemmed it in, sweeping in mad onset of white-topped waves and eddying whirlpools flinging spray high in air.  The stoutest swimmer would be tossed about helplessly in it, rolled over and over, choked, suffocated, sucked under, the life beaten out of him.

For one wild moment Frank thought of seizing Muriel in his arms and springing into the raging flood, but the sheer hopelessness of escape that way checked him.  It was certain death.  Better to turn and face their pursuers.  There was more chance of life in battling with a score or two of Bhutanese swordsmen than with the tumbling, tossing waters.

So, pistol in hand, the three retraced their steps, looking everywhere for a suitable spot to make a stand.  But on either hand the cliffs rose sheer, their faces seamed here and there with cracks, but with never a crevice big enough to shelter them.  They passed the bend; and a few hundred yards beyond it some large rocks fallen from the cliff on one side lay close against its base.

Frank resolved to take their stand here.  It was the only cover visible.  They fitted the holster-stocks to their pistols, converting them into carbines which could be fired from the shoulder, enabling them to aim more accurately at a longer range.  Then while Tashi crept cautiously along the pass to scout, the subaltern and the girl examined the position for defence.  Thus occupied they were startled by shots ringing out, echoing down the vast canyon.  Taking cover they saw their companion running back followed by a body of men, a few mounted, the majority on foot.  Some had fire-arms, others bows, the rest swords.