But a radar reading of Joe’s trajectory showed that he seemed to be heading directly for the atoll. Austin zoomed in on the tiny speck. The monitor showed a palm-studded, handkerchief-sized patch of sand encircled by a coral reef. Nothing unusual, except for a dark streak near one side of the lagoon. He ran through the possibilities: school of fish, coral, undersea vegetation, shadows . . . Nothing seemed to fit. He looked up earlier images of the island: the streak was larger then. He kept going back in time, hour by hour.

As he dug back into the satellite photos, he saw that the streak had disappeared. He went further back, and he stopped in his tracks. A cigar-shaped object had taken the place of the streak. The conning tower protruding from the object identified it as a submarine. He enlarged the image, and did a quick Internet search for an Akula-class submarine. He found a series of pictures, extracted one that had the conning tower in roughly the same position, and placed the two images side by side. The subs were identical.

With growing excitement, Austin backed up in the photo file even further. There was no submarine in the lagoon now, not even a black streak. But he saw a dark spot which, upon enlargement, showed the unmistakable outline of a helicopter. Starting with that shot, he rapidly played the pictures forward like images in a nickelodeon: empty lagoon, helicopter, submarine, no helicopter, black streak shrinking in length.

“Thank you, Caleb Nye,” Austin said loud enough to be heard by Dixon, who leaned over his shoulder to study the computer monitor.

“Who?” the captain asked.

“He was a nineteenth-century whaler, and he just helped me find Joe.”

Austin ran through the series of satellite photos.

“Damn,” the captain said. “I think you’ve got something, Kurt.”

“We need to get in for a closer look. I’m going to need your help.”

Dixon picked up the microphone that connected to the ship’s public-address system.

“I’ll call the ship’s officers together immediately,” he said.

Five minutes later, Austin was in the wardroom, running through the satellite series again for the benefit of the cruiser’s offers. A gunnery officer suggested surrounding the atoll with every ship in the fleet, then launching an invasion of it.

Austin shook his head.

“A full-fledged naval raid is out of the question, in my opinion,” he said. “There simply isn’t enough intelligence available on which to base an attack. One miscalculation might result in a massacre of the lab’s scientific team.”

The officer didn’t like being rebuffed.

“Who’s calling the shots here, Captain?” he asked. “The U.S. Navy or NUMA? That lab is Navy property.”

“That’s true,” Dixon said, “but I’ve got orders from the Navy brass to let NUMA take the lead.”