There was a general sussuration of discontent. It meant the fins would have to put on the harnesses they had only just had the pleasure of removing, on leaving the ship. Still, even Keepiru recognized this was urgent business.

Toshio was briefly busy dropping harnesses into the water. They were supposed to spread naturally into a shape suitable for a dolphin to slip into easily, but inevitably one or two fins needed help fitting his harness to the small nerve amplifier socket each had just above his left eye.

Toshio finished the job quickly, with the unconscious ease of long practice. He was worried about Ssassia, a gentle fin who had always been kind and soft-spoken to him.

"Hikahi," he said as the leader swam past, "do you want me to call the ship?"

The small gray Tursiops female rose up to face Toshio. "Negative, Ladder-runner. We obey orders. Spy-sats may be high already. Set your speed sled to return on auto if we fail to survive what is in the sssoutheast."

"But no one's seen any big animals…"

"Thatt is only one possibility. I want word to get back whatever our doom… should even rescue fever strike us all."

Toshio felt cold at the mention of "rescue fever." He had heard of it, of course. It was something he had no desire at all to witness.

They set out to the southeast in skirmish formation. The fins took turns gliding along the surface, then diving to swim alongside Toshio. The ocean bottom was like an endless series of snake tracks — pitted by strange pock-holes like deep craters, darkly ominous. In the valleys Toshio could usually see bottom, a hundred meters or so below, gloomy with dark blue tendrils.

The long ridges were topped at intervals by the shining metal-mounds, like hulking castles of shimmering, spongy armor. Many were covered with thick, ivy-like growths in which Kithrupan fishes nested and bred. One metal-mound appeared to be teetering on the edge of a precipice — the cavern dug by its own tall drill-tree, ready to swallow the entire fortress when the undermining was done.