"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!" the native said. "One of the chemical differences." He came to his feet. The dying instructor was forgotten. The native's hand went out. "Billy, am I glad to see you. I was afraid you wouldn't recognize me in spite of the tune I was whistling as I walked past you on the street."