enly he had an answer from an alley.

"Here, sir--here I am. Are you looking for me? I'm sorry, sir." Billy
himself appeared in the alley.

Reassured at the sight of the youth, but angry, the instructor moved
into the alley. "What is the meaning of this? You have alarmed all of
us."

"I'm awfully sorry, sir. But I saw something back here that interested
me, and I stopped to take a look. I hope you will forgive me." His
manner was so contrite and his chagrin so complete that the instructor
had no choice but to forgive him.

"Of course, Billy. But you mustn't do anything like this again. It might
be dangerous."

"I won't, sir. I promise. But I wonder, since you are here, if you would
be good enough to explain to me the thing I saw back here. It will only
take a minute."

"What is it?"

"It's something in one of the houses. I came back looking at something
else, then caught a glimpse of this. If you will come into the back yard
you can see it. I would really like to have you explain it to me, sir.
You are always so clear in your explanations." Billy Kasker's manner was
very winning.

"Well, if it will only take a minute--" The instructor followed Billy
into the back yard. At the rear was a shed with an open window. A plot
of grass separated the shed from the house. On the second floor of the
house, a window had been shattered.

"There's something up there in that broken window. If you will come
here, sir, you can see it better."

"Um. Ah! Oh, yes." The instructor's back was to the open window of the
shed. He stared upward at the house.

Two brown-coated arms came out of the window of the shed and clamped a
fierce grip around his throat, jerking him backward against the wall. He
grabbed frantically for the _Thor_ gun.

The face of the brown native appeared in the window of the shed. "Get
that gun, Billy!"

Billy Kasker was already in action. He snatched the gun from the
instructor's flailing hands.

The brown native leaned from the window. Muscles bulging in his powerful
arms, he lifted the instructor upward and through the window. A thump
came from inside the shed. Billy Kasker, _Thor_ gun ready for use, went
through the door.

The instructor was writhing on the floor. The native had a knee on his
chest, a knife in his hand.

"This is for the race you _think_ you've conquered!" the native said. He
plunged the knife into the instructor's throat. Green liquid spurted
from the wound.

"Green blood!" t