Austin wheeled the Torpedo 2000 around in a tight arc. He glided past the beach and homed in on a silvery pinpoint that blinked like a firefly on a summer night. Zavala was hovering at midwater and flashing his light as a homing beacon. When Austin got closer, Zavala adjusted his light to flood pattern and pointed the beam toward the face of the undersea wall that rose to become the chin of Imam's Point.

Austin was looking at a huge pile of rubble that resembled a landslide one might see in a mountain valley. The sea bottom below the slide was littered with hundreds of chunks of rock and concrete obviously flung there with great force, most likely by an explosion.

“Not exactly what I'd call a welcome mat,” Austin said. With short fluttering fin strokes, he swam up the face of the rubble pile. If this was the entrance to the pen, no submarines would be using it soon. He swam back and forth searching for an opening, but the blockage was complete.

Zavala floated up beside him. “So much for my dreams of beautiful Russian women.”

Austin scanned the rubble, then swam over to a slab about six feet tall and half as wide that stood like a giant l gravestone in a more or less vertical position. A pair of steel rods protruded from the top, like antennae on an insect.

“If we could topple this slab, maybe we could start a slide that would open up this mess.”

“Not a bad idea. Too bad we forgot to pack dynamite.”

“We may not need it. Remember what Archimedes said?”

“Sure, he's the guy who runs the Greek restaurant down the street, He said 'Eat here or to go?' ”

“I'm talking about the other Archimedes.”

“Oh, that one, He said, 'Eureka!' ”

“He also said, 'Give me a place to stand and I will move the earth.' ”

Zavala stared at the steel rods. “Archimedes was into levers and fulcrums, as I recall.”

“Eureka,” Austin said, swimming up the rock slide until he was above the slab. He squeezed in between the concrete and the cliff, braced his back against the wall and placed his feet on one of the rods. Zavala took a position beside Austin with his feet on the other rod.

“Let's see if we can move a smaIl piece of the world,” Austin said, “On three.”

They pushed against the rods and the slab tilted a few inches before settling back into place. The air tanks got in the way, so they adjusted them and tried again. The slab tipped precariously this time. For a moment, it seemed as if the block would go over, but despite their shoving and grunting, it rocked back into place.