y the deep valley
that sheltered the heart of the Moulton Project.

Hot springs joined to form a steaming river. Vegetation grew savagely
under the huge sun. The air, kept at almost constant temperature by the
blanketing effect of the hot springs, was stagnant and heavy.

But up above, high over the copper cables that crossed every valley
where men ventured, the eternal wind of Mercury screamed and snarled
between the naked cliffs.

Three concrete domes crouched on the valley floor, housing barracks,
tool-shops, kitchens, store-houses, and executive quarters, connected by
underground passages. Beside the smallest dome, joined to it by a
heavily barred tunnel, was an insulated hangar, containing the only
space ship on Mercury.

In the small dome, John Moulton leaned back from a pile of reports, took
a pinch of Martian snuff, sneezed lustily, and said.

"Jill, I think we've done it."

The grey-eyed, black-haired young woman turned from the quartzite window
through which she had been watching the gathering storm overhead. The
thunder from other valleys reached them as a dim barrage which, at this
time of Mercury's year, was never still.

"I don't know," she said. "It seems that nothing can happen now, and
yet.... It's been too easy."

"Easy!" snorted Moulton. "We've broken our backs fighting these valleys.
And our nerves, fighting time. But we've licked 'em!"

He rose, shaggy grey hair tousled, grey eyes alight.

"I told the IPA those men weren't criminals. And I was right. They can't
deny me the charter now. No matter how much Caron of Mars would like to
get his claws on this radium."

He took Jill by the shoulders and shook her, laughing.

"Three weeks, girl, that's all. First crops ready for harvest, first
pay-ore coming out of the mines. In three weeks my permanent charter
will have to be granted, according to agreement, and then....

"Jill," he added solemnly, "we're seeing the birth of a world."

"That's what frightens me." Jill glanced upward as the first flare of
lightning struck down, followed by a crash of thunder that shook the
dome.

"So much can happen at a birth. I wish the three weeks were over!"

"Nonsense, girl! What could possibly happen?"

She looked at the copper cables, burning with the electricity running
along them, and thought of the one hundred and twenty-two souls in that
narrow Twilight Belt--with the fierce heat of the Sunside before them
and the spatial cold of the Shadow s