the checkpoint, but I'd rather go back to
Earth."

"Well, you can't have everything."

The last of the guards entered the assembly room and dogged the door
shut. Barrent waited. After a while, he felt the ship vibrate. It was
beginning its departure.

He had learned some valuable information. Apparently all or most of the
guards got off at the checkpoint. Did that mean that another detachment
of guards got on? Probably. And a checkpoint implied that the ship was
searched for escaped prisoners. It was probably only a perfunctory
search, since no prisoner had escaped in the history of Omega. Still, he
would have to figure out a way of avoiding it.

But he would face that when the time came. Now he felt the vibration
cease, and he knew that the ship had left the surface of Omega. He was
aboard, unobserved, and the ship was on its way to Earth. So far,
everything had gone according to plan.

* * * * *

For the next few hours, Barrent stayed in the storage room. He was
feeling very tired, and his joints had begun to ache. The air in the
small room had a sour, exhausted smell. Forcing himself to his feet,
Barrent walked to the air vent and put his hand over it. No air was
coming through. He took a small gauge out of his pocket. The oxygen
content of the room was falling rapidly.

Cautiously he opened the storeroom door and peered out. Although he was
dressed in a perfect replica of guard's uniform, he knew he couldn't
pass among men who knew each other so well. He had to stay in hiding.
And he had to have air.

The corridors were deserted. He passed the guard assembly room and heard
faint murmurs of conversation inside. The green light glowed brightly
over the door. Barrent walked on, beginning to feel the first signs of
dizziness. His gauge showed him that the oxygen content in the corridor
was starting to fall.

The Group had assumed that the air system would be used throughout the
ship. Now Barrent could see that, with only guards and crew aboard,
there was no need to supply air for the entire ship. There would be air
in the little man-inhabited islands of the guardroom and the crew's
section, and nowhere else.

Barrent hurried down the dim, silent corridors, gasping for breath. The
air was rapidly growing bad. Perhaps it was being used in the assembly
room before the ship's main air supply was touched.

He passed unlocked doors, but the green bulbs above them were unlighted.
H