forty level, a patrol ship that had caught the signal came corkscrewing
down the red shaft to stand by for emergency work.... Chet called her
commander from the cabin of Diane's ship. A word of thanks--Chet's
number--and a dismissal of the craft. Then the white lights signaled
"all clear" and the hold-down levers let go with a soft hiss--

The feel of the controls was good to his hands; the ship roared into
life. A beautiful little cruiser, this ship of Diane's; her twin
helicopters lifted her gracefully into the air. The column of red light
had changed to blue, the mark of an ascending area; Chet touched a
switch. A muffled roar came from the stern and the blast drove him
straight out for a mile; then he swung and returned. He was nosing up as
he touched the blue--straight up--and he held the vertical climb till
the altimeter before him registered sixty thousand.

Traffic is north-bound only on the sixty-level, and Chet set his ship on
a course for the frozen wastes of the Arctic; then he gave her the gun
and nodded in tight-lipped satisfaction at the mounting thunder that
answered from the stern.

Only then did he read again the message on a torn fragment of
telautotype paper. "Harkness," was the signature; and above, a brief
warning and a call--"Danger--must leave at once. You get ship and stand
by. I will meet you there." And, for the first time, Chet found time to
wonder at this danger that had set the hard-headed, hard-hitting Walt
Harkness into a flutter of nerves.

* * * * *

What danger could there be in this well-guarded world? A patrol-ship
passed below him as he asked himself the question. It was symbolic of a
world at peace; a world too busy with its own tremendous development to
find time for wars or makers of war. What trouble could this man
Schwartzmann threaten that a word to the Peace Enforcement Commission
would not quell? Where could he go to elude the inescapable patrols?

And suddenly Chet saw the answer to that question--saw plainly where
Schwartzmann could go. Those vast reaches of black space! If
Schwartzmann had their ship he could go where they had gone--go out to
the Dark Moon.... And Harkness had warned Chet to get their ship and
stand by.

Had Walt learned of some plan of Schwartzmann's? Chet could not answer
the question, but he moved the control rheostat over to the last notch.

From the body of the craft came an unending roar of a generator where