re are two of us now, Astro!" said Ross.

Astro nodded slowly. "That's right. Two of you!" Suddenly he dove toward
the two men, arms outstretched. With one mighty swipe of the wrench he
knocked Quent unconscious. Ross was hurled against the bulkhead by the
impact but managed to stay on his feet. Desperately he tore the
paralo-ray rifle from his shoulder, but before he could level it, Astro
was upon him, wrenching it out of his grasp. Pushing Ross away, he
calmly broke it in two and threw the pieces to one side. Then he faced
the black-clad spaceman squarely.

"I was a kid when I first saw you, Ross," he said between his teeth. "So
you had me fooled like everyone else. When your brother showed up at the
Academy with his ears in good shape, I thought it was a curious
coincidence two guys should look so much alike. And on Titan, when you
had me hauling up those boxes, you wore your hat all the time, along
with the oxygen mask, so I didn't think anything of it. But now I know!"

[Illustration]

All the while Astro talked, the two men circled each other like two
wrestlers, each waiting for his opponent to make a mistake.

"So you know!" sneered Ross. "All right, wiper, come on!"

The black-suited spaceman suddenly dove straight at Astro and the cadet
caught the full force of his body in his stomach. He sprawled on the
deck, gasping. Miles was on top of him in a second, hands at Astro's
throat.

[Illustration]

Fire danced in the cadet's brain as Ross Miles' steely fingers closed
around his windpipe. Slowly, with every ounce of strength he had in his
body, Astro grasped Miles' wrists in his hands and began squeezing. The
fingers around the muscular wrists were the fingers of a boy filled
with hate and revenge. Slowly, very slowly, as the seconds ticked away
and the wind whistled raggedly in his throat, Astro increased the
enormous pressure.

Now he felt the fingers around his throat begin to relax a little, and
then a little more, and he kept tightening the pressure of his mighty
hands. Expressions of surprise and then pain spread across Miles' face
and he finally relaxed his grip around Astro's throat. He struggled to
free himself from the viselike grip but it was hopeless.

Astro continued to apply pressure. He forced Miles up from his chest and
then up on his feet, never relenting. Miles' face was now twisted in
agony.

They stood on the deck, face to face, for almost a minute in silent
struggle. There seemed