the pieces to one side.

The fires were started and green wood was thrown on them, to make them
smoulder and smoke for as long as possible. Then the unicorns were
coming on to the stockade and every person inside it went into the
concealment of the shelters.

Lake had already given his last order: There would be absolute quiet
until and if the unicorns left; a quiet that would be enforced with fist
or club wherever necessary.

The unicorns were still outside when morning came. The fires could not
be refueled; the sight of a man moving inside the stockade would bring
the entire herd charging through. The hours dragged by, the smoke from
the dying fires dwindled to thin streamers. The unicorns grew
increasingly bolder and suspicious, crowding closer to the walls and
peering through the openings between the rails.

The sun was setting when one of the unicorns trumpeted; a sound
different from that of the call to battle. The others threw up their
heads to listen, then they turned and drifted away. Within minutes the
entire herd was gone out of sight through the woods, toward the north.

Lake waited and watched until he was sure the unicorns were gone for
good. Then he ordered the All Clear given and hurried to the south wall,
to look down across the barren valley and hope he would not see what he
expected to see.

Barber came up behind him, to sigh with relief. "That was close. It's
hard to make so many people stay absolutely quiet for hour after hour.
Especially the children--they don't understand."

"We'll have to leave," Lake said.

"Leave?" Barber asked. "We can make this stockade strong enough to hold
out unicorns."

"Look to the south," Lake told him.

Barber did so and saw what Lake had already seen; a broad, low cloud of
dust moving slowly toward them.

"Another herd of unicorns," Lake said. "John didn't know they
migrated--the Dunbar Expedition wasn't here long enough to learn that.
There'll be herd after herd coming through and no time for us to
strengthen the walls. We'll have to leave tonight."

* * * * *

Preparations were made for the departure; preparations that consisted
mainly of providing each person with as much in the way of food or
supplies as he or she could carry. In the 1.5 gravity, that was not
much.

They left when the blue star rose. They filed out through the northern
gate and the rear guard closed it behind them. There was almost no
conversation