"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."