'll we land, Detis?" Mado called from the control cabin.

"Vlor-urdin. That is their chief city. I'll guide you to the
location."

* * * * *

They took up their places at the ports and scanned the surface of the
satellite as Mado dropped the ship into its atmosphere. A far
different scene was presented than on Europa. The land was seamed and
scarred, the colors of the foliage somber. Grays and browns
predominated and the jungles seemed impenetrable. A river swung into
view and its waters were black as the deepest night, its flow
sluggish. A rank mist hung over the surface.

"The river of Charis!" exclaimed Detis. "Follow it, Mado. No, the
other direction. There! It leads directly to Vlor-urdin."

By good chance they had entered the atmosphere at a point not far from
their destination. In less than an hour by the _Nomad's_ chronometer
the towers of Vlor-urdin were sighted.

It was a larger city than Pala-dar and of vastly different appearance.
A hollow square of squat buildings enclosed the vast workshops and
storage space of the fleet of war vessels. Their huge spherical bulks
rose from their cradles in tier after tier that stretched as far as
the eye could reach when the _Nomad_ had dropped to a level but
slightly above the tips of the highest spires. The spires were
everywhere, decorative towers at the corners of the squat buildings.
Everything was black, the vessels of the fleet, the squat buildings
and the spires of Vlor-urdin. Death was in the air. Rank vapor drifted
in through the opened ports. There was silence in the city below them
and silence in the _Nomad_.

Ora shuddered and drew closer to him. Carr was aware of her nearness
and a lump rose in his throat. A horrible fear assailed him. Fear for
the safety of the dainty Europan at his side. He found her hand;
covered it protectingly with his own.

CHAPTER VII

_Rapaju_

Detis was setting up and adjusting the complicated mechanisms of his
little black case. A dozen vacuum tubes lighted, and a murmur of
throbbing energy came from a helix of shining metallic ribbon that
topped the whole. Flexible cables led to a cap-like contrivance which
Detis placed on his head. He frowned in concentration.

"The psycho-ray apparatus." Ora explained. "He's sending a message to
the city."

Evidently the influence of the ray was directive. They had no inkling
of the thoughts transmitted from the alert brain of the scientist but,
f