mes he had thought he would go mad. The everlasting routine, the
meaningless march of hours. The work period, the sleep period ... the
work period, the sleep period ... endless monotony, an existence without
a purpose. Men buried alive in space.

"John Moore Mallory," said a voice.

Mallory heard, but he did not stir. An awful thought crossed his mind.
Now he was hearing voices calling his name!

"John Mallory," said the voice again.

Mallory slowly turned about and as he turned he started from his chair.

A man stood in the cell! A man he had never seen before, who had come
silently, for there had been no screech of opening door.

"You are John Moore Mallory, aren't you?" asked the man.

"Yes, I am Mallory. Who are you?"

"Gregory Manning."

"Gregory Manning," said Mallory wonderingly. "I've heard of you. You're
the man who rescued the Pluto Expedition. But why are you here? How did
you get in?"

"I came to take you away with me," said Greg. "Back to Callisto. Back to
any place you want to go."

Mallory flattened himself against the partition, his face white with
disbelief. "But I'm in a prison ship. I'm not free to go and come as I
please."

Greg chuckled. "You are free to go and come as you please from now on,"
he said. "Even prison ships can't hold you."

"You're mad," whispered Mallory. "Either you're mad or I am. You're a
dream. I'll wake up and find you gone."

Manning stood in silence, looking at the man. Mallory bore the marks of
prison on him. His eyes were haunted and his rugged face was pinched and
thin.

"Listen closely, Mallory," said Greg softly. "You aren't going mad and
I'm not mad. You aren't seeing things. You aren't hearing things. You're
actually talking to me."

* * * * *

There was no change in the other's face.

"Mallory," Greg went on, "I have what you've always needed--means of
generating almost unlimited energy at almost no cost, the secret of the
energy of matter. A secret that will smash Interplanetary, that will
free the Solar System from Spencer Chambers. But I can't make that
secret available to the people until Chambers is crushed, until I'm sure
that he can't take it from me. And to do that I need your help."

Mallory's face lost its expression of bewilderment, suddenly lighted
with realization. But his voice was harsh and bitter.

"You came too late. I can't help you. Remember, I'm in a prison ship
from which no one can escape. Y