metropolis
consisted of perfectly square buildings pierced by many windows to
indicate that each housed a large number of inmates. But here and
there grotesque turrets lanced the sky, and symbolic domes arched
above the surrounding flat metal roofs.

One building in particular they noticed. This was an enormous
structure in the shape of a half-globe that reared its spherical
height less than an eighth of a mile from the building they were in.
It was situated off to their right at the foot of a vast, high-walled
enclosure whose near end seemed to be formed by the right wall of
their prison. They could only see it by leaning far out of the
window; and it would not have come to their attention at all had they
not heard it first--or, rather, heard the sound of something within
it: for from it came a curious whining hum that never varied in
intensity, something like the hum of a gigantic dynamo, only greater
and of a more penetrating pitch.

"Sounds as though it might be some sort of central power station,"
said Brand. "But what could it supply power for?"

"Give it up," said Dex. "For their damned shock-tubes, perhaps, among
other things--"

He broke off abruptly as a sound of sliding bolts came from the
doorway. The two men whirled around to face the door, their fists
doubling instinctively against whatever new danger might threaten
them.

* * * * *

The door was opened and two of their ugly, towering enemies came in,
their tubes held conspicuously before them. Behind came another
figure; and at sight of this one, so plainly not of the race of
Jupiter, the Earthmen gasped with wonder.

They saw a girl who might have come from Earth, save that she was
taller than most Earth women--of a regal height that reached only an
inch or two below Brand's own six foot one. She was beautifully
formed, and had wavy dark hair and clear light blue eyes. A sort of
sandal covered each small bare foot; and a gauzy tunic, reaching from
above the knee to the shoulder, only half shielded her lovely figure.

She was bearing a metal container in which was a mess of stuff
evidently intended as food. The guards halted and stepped aside to let
her pass into the room. Then they backed out, constantly keeping Dex
and Brand covered with the tubes, and closed and barred the door.

The girl smiled graciously at the admiration in the eyes of both the
men--a message needing no inter-planetary interpretation. She