ey and his wife
had withdrawn to one side and were talking in low tomes to one
another. Quite thoughtlessly Jon turned the lens on them and clicked
the shutter.

Langley became rust-red throughout the vast expanse of his neck and
face. "Here!" he said, "what are you doing?"

"Nothing," said Jon.

"You took a picture of me," snarled Langley. "Give me the plate at
once."

Jon Rogeson got a bit red himself. He was not used to being ordered
around. "I'll be damned if I will," he said.

Langley growled something I couldn't understand, and turned his back
on us. The she who was called his wife looked startled and worried.
Her eyes were beseeching as she looked at Jon. A message there, but I
could not read it. Jon looked away.

Langley started walking back to the half-track alone. He turned once
and there was evil in his gaze as he looked at Jon. "You will lose
your job for this impertinence," he said with quiet savagery, and
added, enigmatically, "not that there will be a job after this week
anyway."

Builders may appear to act without reason, but there is always a
motivation somewhere in their complex brains, if one can only find it,
either in the seat of reason, or in the labyrinthine inhibitions from
their childhood. I knew this, because I had studied them, and now
there were certain notions that came into my brain which, even if I
could not prove them, were no less interesting for that.

* * * * *

The time had come to act. I could scarcely wait for darkness to come.
There were things in my brain that appalled me, but I was now certain
that I had been right. Something was about to happen to Phobos, to all
of us here--I knew not what, but I must prevent it somehow.

I kept in the shadows of the shabby buildings of Argon City, and I
found the window without effort. The place where I had spied upon the
wife of Langley to my sorrow the other night. There was no one there;
there was darkness within, but that did not deter me.

Within the airdrome which covers Argon City the buildings are loosely
constructed, even as they are on Earth. I had no trouble, therefore,
opening the window. I swung a leg up and was presently within the
darkened room. I found the door I sought and entered cautiously. In
this adjacent compartment I made a thorough search but I did not find
what I primarily sought--namely the elusive reason for Langley's visit
to Phobos. It was in a metallic overnight bag tha