rop
blast. Rick took the suitcase that was handed to him by Dr. Gordon, who
leaped lightly to the ground after his luggage.

The scientist, a short, wiry man with gray hair cropped crew-cut
fashion, waved to the pilot, then motioned the young people back as the
pilot turned with a blast of his prop and taxied to take-off position in
front of the lab.

Because of the racket, no one tried to talk until the plane was nearly
out of earshot. Then Barby spoke for all of them as they walked to the
house. "We thought you'd never get here!"

Dr. Gordon smiled his pleasure at being home again. He shook hands with
the boys. "You've no idea how nice and green this island looks after the
Nevada desert. And you've no idea how hungry I am! Is it too late for
lunch?"

Mrs. Brant answered him from the porch. "You have just two minutes to
wash up and come to the table, John!"

Hartson Brant appeared behind her. He shook hands with Dr. Gordon as the
three young people escorted him to the porch. "Welcome home, John."

"Thanks, Hartson. It's good to be back. Where are the others? Zircon,
Weiss, and Winston? I know Tony and Howard are off on an expedition, but
I thought the others were home."

"They are. Parnell Winston is probably having lunch at his cottage.
Hobart and Julius are in New York, examining some new equipment for the
lab. They'll be back tonight."

Rick was dying to ask questions, but he knew this was not the right
time. At lunch, perhaps, they might be given some details.

John Gordon looked at him and grinned. "Here's Rick Brant," he declared,
"politely holding his tongue when he's about to pop like a firecracker
with questions. Your self-control does you credit, Rick. Want one bit of
data to chew on while you're waiting?"

Rick gulped, then returned the grin. "Yes, sir!"

John Gordon lowered his voice to a confidential pitch. "We have an
enemy," he stated. "What kind of enemy may be seen clearly in the name
by which he goes." He paused.

"What name?" Rick asked impatiently.

"_Homo Terrestrialis._"

John Gordon turned and hurried upstairs to his room to wash up for
lunch.

Rick stared after him. What in the name of a simple-minded spacefish did
that mean?

_Homo Terrestrialis._

Man of Earth.

Earthman!

CHAPTER II

Assignment: Rocket Base

Rick turned the phrase over and over in his head, trying to make sense
out of it. Earthman? Who wasn't an earthman? The whole human race was
compose