the day its masters had either died within it or left it for the last
time, perhaps centuries before.

"This is one way into the forbidden city," Sssuri announced. "Once
they stationed guards here."

Dalgard had been about to suggest a closer inspection of the dome but
that remark made him hesitate. If it had been one of the
fortifications rimming in a forbidden ground, there was more than an
even chance that unwary invaders, even this long after, might stumble
into some trap still working automatically.

"Do we go upriver?" He left it to Sssuri, who had the traditions of
his people to guide him, to make the decision.

The merman looked at the dome; it was evident from his attitude that
he had no wish to examine it more closely. "They had machines which
fought for them, and sometimes those machines still fight. This river
is the natural entrance for an enemy. Therefore it would have been
well defended."

Under the sun the green reach of the delta had a most peaceful
appearance. There was a family of duck-dogs fishing from the beach,
scooping their broad bills into the mud to locate water worms. And
moth birds danced in the air currents overhead. Yet Dalgard was ready
to agree with his companion--beware the easy way. They dipped their
paddles deep and cut across the river current toward the cliffs to the
north.

Two days of steady coastwise traveling brought them to a great bay.