the likeliest
prospect. Neither location was particularly exact, and probably Laird
Martin had expected his directions to be gone into under less
harrowing circumstances than those in which Denver now found himself.
With time for trial and error one could eventually locate the place.

But Denver was hurried. He trod upon one of the markings while he
still sought the elusive shadow apex.

After that, it was a grim race to follow the markings to the old
mines, and to get under cover behind defensible barricades in time to
repel invasion.

They played a nerve-wracking game of hare and hounds in tricky floods
of Earthlight, upon slopes and spills of broken rock, amid a goblin's
garden of towering jagged spires. It was tense work over the bad
going, and the light was both distorted and insufficient. In shadow,
they groped blindly from arrow to arrow. In the patches of Earthglare,
they fled at awkward, desperate speed.

Life and death were the stakes. Life, or a fighting chance to defend
life, possible wealth from the ancient workings, made a glittering
goal ahead. And ever the gray hounds snapped at their heels, with
death in some ugly guise the penalty for losing the game.

Charley was ecstatic. He gamboled and capered, he zoomed and
zigzagged, he essayed quick, climbing spirals and almost came to
grief among the tangled pinnacles on the ridge of the hogback. He
swooped downward again in a series of shallow, easy glides and began
the performance all over again. It was a game for him, too. But a game
in which he tried only to astound himself, with swift, dizzy miracles
of magnetic movement.

Charley enjoyed himself hugely. He was with the two people he liked
most. He was having a spirited game among interlaced shadows and
sudden, substantial obstacles of rock. He nuzzled the fleeing pair
playfully, and followed them after his own lazy and intricate and
incredibly whimsical fashion. His private mode of locomotion was not
bounded by the possibilities involved in feet and tiring legs. He
scampered and had fun.

It was not fun for Tod Denver and Darbor. The girl's strength was
failing. She lagged, and Denver slowed his pace to support her
tottering progress.

Without warning, the mine entrance loomed before them. It was old and
crumbly with a thermal erosion resembling decay.

It was high and narrow and forbiddingly dark.

Tod Denver had brought portable radilumes, which were needed at once.
Inside the portals was