n it to be deserted, so the basket
was brought to rest in a deeply shadowed portion. Immediately they
stepped out, and it was sent swiftly aloft by remote control of a
portable ether-wave that Dantor produced.

They encountered two of the green-bronze guards in one of the passages
below and these challenged the Rulan lads with drawn pistols. The alarm
was out! Fortunately Pegrani had not recognized Tiedus or all would
have been lost. But the Zara was watching every Rulan community and had
instructed her guards to take the Earth men into custody at all costs.
Those remarkable cloaks were all that saved them. They breathed easier
when the guards passed on.

Now they were in a lift, dropping speedily into the depths of the Tritu
Anu. When the cage came to rest they were hustled into a maze of
winding passageways that led ever downward. A wall of damp stone
finally blocked their progress, but at Dantus' touch of a hidden spring
a section of the solid rock swung aside to admit them to a concealed
room where the lights were bright and where a delegation of Rulans
awaited their coming.

With the cloaks of invisibility removed, they were welcomed by Dantor,
a tall white-haired Rulan who was startlingly like his son.

They were a solemn lot, these Rulans of the older generation, but they
gazed on the Earth men with sympathy and understanding. An entirely
different breed from the Llotta.

This room was a secret laboratory, fully equipped for chemical and
physical research. Dantor sat before a smaller replica of the Zara's
crystal ball as he addressed the visitors.

* * * * *

"No doubt you are puzzled," he began, using the language of the Llotta
with an accent that softened its harsh gutturals, "over the calamity
that has befallen you. And it is not to be wondered at. But your own
danger is as nothing compared with the danger that now threatens our
whole solar system. It is to explain that and to ask your cooperation
in warding off the holocaust that I have sent for you.

"Since the destruction of the Tritu Nogaru we Rulans number less than
one thousand, of whom three hundred are here. The Tritu Anu is foremost
of the royal laboratories of Llotta-nar and its work is carried out
entirely by our people. It is only on account of our superior
accomplishments in science that the Llotta have allowed us to exist for
so long a time, and, in this connection, I might say that the Zara has