An odd vibration roused Perry Bergman from a restless sleep, and he was instantly filled with a strange foreboding. The unpleasant murmur put him in mind of fingernails scraping down a blackboard. He shuddered and threw off his thin blanket. As he stood up, the vibration continued. With his bare feet on the steel deck, it now reminded him of a dentist's drill. Just beneath it he could detect the normal hum of the ship's generators and the whir of its air conditioning fans.

"What the hell?" he said aloud, even though there was no one within earshot to provide an answer. He'd helicoptered out to the ship, the Benthic Explorer, the previous evening after a long flight from Los Angeles to New York to Ponta Delgada on the Azorean island of San Miguel. Between the time zone changes and a long briefing about the technical problems his crew was experiencing, he was understandably exhausted. He didn't like being awakened after only four hours of sleep, especially by such a jarring vibration.

Snatching the ship's phone from its cradle he punched in the number for the bridge. While he waited for the connection to go through he peered out the porthole of his V.I.P. compartment on his tiptoes. At five foot seven Perry didn't think of himself as short, just not tall. Outside, the sun had barely cleared the horizon. The ship cast a long shadow across the Atlantic. Perry was looking west over a misty, calm sea whose surface resembled a vast expanse of beaten pewter. The water undulated sinuously with low, widely separated swells. The serenity of the scene belied the goings-on below the surface. The Benthic Explorer was being held in a fixed position by computer driven commands to her propellers as well as to her bow and stern thrusters over a portion of the volcanically and seismically active Mid-Atlantic Ridge, a twelve-thousand-mile-long, jagged range of mountains that bisects the ocean. With the constant extrusion of enormous quantities of lava, submarine explosions of steam, and frequent miniearthquakes, the submerged cordillera was the antithesis of the ocean surface's summer tranquillity.