sentient vegetable life followed
the paths of thin winds, blowing equatorward from the polar caps of
hoarfrost.

The three stellene rings bumped lightly on the ten mile chunk of
captured asteroidal rock and nickel-iron that was Phobos, Mars' nearer
moon. Gravitation was almost nil. There was no need, here, for rockets,
to land or take off. The sun-powered ionics were more than enough.

A small observatory, a U.N.-tended between ground-and-orbit rocket port,
and a few hydroponic garden domes nestled in the jaggedness were about
all that Phobos had--other than the magnificent view of the Red Planet,
below.

Gimp Hines' freckled face shone in the ruddy light. "_I'm_ going down,"
he declared. "Just for a few days, to look around near the Survey
Station. You guys?"

Ramos shrugged, almost disinterested. "People have been there--some
still are. And what good is poking around the Station? But who wants to
goof up, going into the thickets? Others have done that, often enough.
Me for Pallastown, and maybe lots farther, pal."

Frank Nelsen wasn't that blase. On the Moon, he had seen some of the old
Mars of advanced native technology, now long extinct. But there was also
the recent Mars of explorers and then footloose adventurers, wondering
what they could find to do with this quiet, pastel-tinted world of
tremendous history. Then had come the colonists, with their tractors and
their rolls of stellene to make sealed dwellings and covered fields in
that thin, almost oxygenless atmosphere.

But their hopes to find peace and isolation from the crowded and
troubled Earth by science and hard work even in so harsh a place, had
come into conflict with a third Mars that must have begun soon after the
original inhabitants had been destroyed. Though maybe it had had its
start, billions of years before, on the planets of another star. The
thickets had seemed harmless. Was this another, _different_
civilization, that had risen at last in anger, using its own methods of
allergy, terrible repellant nostalgia, and mental distortions?

Frank felt the call of mystery which was half dread. But then he
shrugged. "Uh-uh, Gimp. I'd like to go down, too. But the gravity is
twice that of the Moon--getting up and down isn't so easy. Besides, once
when I made a stopover in space, after a nice short hop, I got into
trouble. I'll pass this one up. I'd like to talk to Mitch Storey,
though."

They all tried to reach him, beaming the Survey Station a