Another streak of movement slashed across his field of vision.

This time he managed to maintain his grip on the controls. He saw more eelpouts, like fat snakes hanging head down as though suspended in space. The water spewing from the vent below was rich in heated hydrogen sulfide, a chemical that was toxic and incompatible with life. But even in these black and poisonous waters, had managed to bloom, in shapes fantastic and beautiful. Attached to the canyon wall were swaying Riftia worms, six feet long, with feathery scarlet headdresses. He saw clusters of giant clams, white-shelled, with tongues of velvety red peeking out.

And he crabs, eerily pale and ghostlike as they scuttled among the crevices.

Even with the air-conditioning unit running, he was starting to feel the heat.

Six thousand meters. Water temperature one hundred eighty degrees. In the plume itself, heated by boiling magma, the temperatures would be over five hundred degrees. That life could even here, in utter darkness, in these poisonous and superheated waters, seemed miraculous.

"I'm at six thousand sixty," he said. "I don't see it." In his earphone, Helen's voice was faint and crackling. "There's a shelf jutting out from the wall. You should see it at around six thousand eighty meters."

"I'm looking."

"Slow your descent. It'll come up quickly."

"Six thousand seventy, still looking. It's like pea soup down here. Maybe I'm at the wrong position."

" ... sonar readings ... collapsing above you!" Her message was lost in static.

"I didn't copy that. Repeat."

"The canyon wall is giving way! There's debris falling toward you. Get out of there!" The loud pings of rocks hitting the hull made him jam the joysticks forward in panic. A massive shadow plummeted down through the murk just ahead and bounced off a canyon shelf, sending a fresh rain of debris into the abyss. The pings accelerated.