o perform. The swing made wide circles,
graceful glides as the thing explored the air currents.

Searching--it was plainly searching for something. Just as plainly it
could not be hunting for him, for his presence on that roof would
have been uncovered at once. But the machine was--it must be--out of
sight of the warriors in the street. How could they keep in touch with
it if it located what they sought? Unless it had some built-in
signaling device.

Determined to keep it in sight, Raf risked a jump from the parapet of
the building where he had taken cover to another roof beyond, running
lightly across that as the hound bobbed and twisted, away from its
masters, out across the city in pursuit of some mysterious quarry....

* * * * *

The climb which had looked so easy from the street proved to be more
difficult when Dalgard actually made it. His hours of swimming in the
river, the night of broken rest, had drained his strength more than he
had known. He was panting as he flattened himself against the wall,
his feet on one of the protruding bands of colored carving, content to
rest before reaching for another hold. To all appearances the city
about him was empty of life and, except for the certainty of the
merpeople that the alien ship and its strange companion had landed
here, he would have believed that he was on a fruitless quest.

Grimly, his lower lip caught between his teeth, the scout began to
climb once more, the sun hot on his body, drawing sweat to dampen his
forehead and his hands. He did not pause again but kept on until he
stood on the top of the shortened tower. The roof here was not flat
but sloped inward to a cuplike depression, where he could see the
outline of a round opening, perhaps a door of sorts. But at that
moment he was too winded to do more than rest.

There was a drowsiness in that air. He was tempted to curl up where he
sat and turn his rest into the sleep his body craved. It was in that
second or so of time when he was beginning to relax, to forget the
tenseness which had gripped him since his return to this ill-omened
place, that he touched--

Dalgard stiffened as if one of his own poisoned arrows had pricked his
skin. Rapport with the merpeople, with the hoppers and the runners,
was easy, familiar. But this was no such touch. It was like contacting
something which was icy cold, inimical from birth, something which he
could never meet on a plain of unde