ble _thunk_. The Tibetan fell forward
on his face.

Frightened out of his wits, Rick rolled him over, pulled aside the
sheepskin coat he wore and put his ear on the man's chest. Then he
sighed with relief. He hadn't swung too hard. For a moment he had feared
that the blow had killed the man. And that would have been almost as
effective as holding the rifle barrel to his own head, because he still
had no idea of where to go without the guide.

He debated for a moment, then lifted the Tibetan, dragged him to the
boat and dumped him in. It was a flat-bottomed craft with blunt ends and
primitive oar-locks. The oars were poles with round disks of wood on the
ends.

He collected the candle and the camera, placed them on a thwart, and
went to work on the rope. It was reeved through an iron ring that jutted
from the stone. The sight gave him heart. Where there was iron, men came
often. At least he was sure that held true in this case. But his victory
had spurred him on and he didn't want to sit quietly and wait. He wanted
to keep going.

He untied the knot, blew out the candle, shipped the oars and pushed
off. Something was on the other side of this Lake of Darkness. He
couldn't imagine what, but he intended to find out!

CHAPTER XVII

Through a Pair of Dark Glasses

Somewhere, perhaps, beyond the Lake of Darkness, was Long Shadow.

Rick felt certain of it. The Tibetan who lay unconscious at his feet had
been going somewhere. He had walked steadily and purposefully, with some
definite destination in mind. What was more logical than to assume that
the Tibetan had been heading for the hidden plant where heavy water was
being produced?

Once the plant was found, Long Shadow would be found there, also. Even
if he were not there at the moment, he would come. And when he did, Rick
intended to do something about it. He had no definite plans. He only
knew that somehow he would force Long Shadow to unlock the gate to the
outer world.

His oars dipped rhythmically as he pulled out into the lake. The
infrared light was directed toward a jutting edge of limestone on the
shore he had just left. He was using the rock formation as a marker so
he could steer a straight course.

He wondered about his friends. Were they lost, too? Or had they managed
to keep to the right trail by following the tiny drops of candle wax?
The odd tin candleholder explained why there wasn't more wax to follow.
The holder caught most, but not a