"False alarm," Hui said, smiling deferentially and nodding. "I'm very sorry for the inconvenience."

The marines looked around suspiciously for a moment, rifles at the ready. Hui continued to smile and nod, and after a moment-with a last look at Crane-the two ducked back outside and resumed their positions flanking the entrance. Hui closed the door once again, then turned toward Crane. Her smile immediately turned sheepish.

"Sorry," she said.

"You're sorry? I just made a mistake that would put a schoolboy to shame."

"No. I thought you knew the guidelines. I overreacted, I…Well, I guess we're all a little tense down here. Every test we've done shows these things to be inert, benign. Still…"

Her voice trailed off and they stood a moment in silence. Crane exhaled slowly, feeling his heart decelerate. His fingertips still tingled.

Hui seemed to be pondering something. "Actually," she said slowly, "I think you might have just done me a favor, Dr. Crane."

"How's that?" Crane asked, absently rubbing his fingertips.

"You've given me something else to analyze. Because now, the marker is emitting two kinds of electromagnetic radiation."

Crane looked at her. "You mean-"

"Yes." Hui pointed at her instrumentation. "It's still generating infrared as well as visible light."

Once again, Crane approached the object, a little warily this time. It floated there before him, shimmering, its edges wavering ever so slightly, like the delicate, inconstant lines of a mirage. "Why would it be doing that?" he murmured.

"That's the question, isn't it, Dr. Crane?"

Crane peered at it. "It couldn't have anything to do with its method of propulsion-could it?"

"That seems highly unlikely."

"Self-defense mechanism?"

"You mean, to make you let go of it? Equally unlikely. Something as sophisticated as this would have more effective ways to protect itself. Besides, we tried to damage one-they're impervious to everything we've thrown at them. Your fingers couldn't be much of a threat."

Crane circled the marker, frowning. He still felt a little shaky from the adrenaline rush of fright. Picking up a plastic test tube, he very carefully maneuvered it up and around the floating sentinel, caught it, then sealed the tube with a red rubber stopper and paused to examine it. The tiny entity hovered at the precise center of the test tube, supremely oblivious.

"Asher thinks it's a message of some sort," he said. "The on-off pulses of light are a digital code."

Hui nodded. "A logical conclusion."

"I wonder how he's doing," Crane said, more to himself than her. He felt guilty for not connecting with the chief scientist. The last time he'd spoken to Asher had been in his stateroom, when Spartan and his marines had burst in. He'd been so busy since then that he'd simply had no time to contact the man or seek him out.

"I'll send him an e-mail," Ping said. She sat at her desk and began to type. She paused, frowned, then typed again. "That's funny," she said.

"What is?" Crane said, stepping toward her.

"I'm getting network errors." She pointed at the screen. "Look. Maximum allowable dropped packets exceeded."

"What kind of network are you running?"

"Standard 802.11g wireless, the same kind the entire Facility uses." Hui typed some more commands. "There-same thing again."

"I've never had any problems with the network in the Medical Suite."

"First time it's ever happened to me. Always been rock solid before." Hui retyped the commands. "Okay. Got the e-mail through on the third try."

But Crane was still thinking. "What's the frequency band of an 802.11g wireless network?" he asked.

"Five point one gigahertz. Why?" Hui turned from the computer screen to face him. "You don't suppose-"

"That something's interfering with it? Good question. You have any other five point one gigahertz devices in this lab?"

"Nope. Only the wireless network is transmitting on that frequency…"

Hui's voice faltered. For a moment, scientist and doctor looked at each other. Then-as if with a single thought-they both turned toward the little marker hovering serenely in the test tube Crane was holding.

Hui rose from her chair, walked to a nearby lab table, and fished through an assortment of meters and handheld devices until she located an analyzer. She stepped up to the floating object, held the analyzer before it, peered at its tiny screen.

"My God," she said. "It's transmitting on five point one gigahertz, as well."

"It's communicating on three frequencies," Crane said.

"Three that we know of. But all of a sudden I'm willing to bet there are more. Maybe lots more."

"And you're sure this is a new phenomenon?"

"Positive. There was only the single visible band of light-nothing else."

Crane stared at the tiny hovering thing. "What do you think happened?" he murmured.

Ping gave him a curious smile. "It seems you woke it up, Dr. Crane."

Then she stepped back to her desk, sat down, and began to type feverishly.

28

"CO₂ scrubbers?"

"Check."

"Servo and gimbal control?"

"Check."

"Baffle integrity?"

"One hundred percent."

"Inertial guidance indicators?"

"Green."

"EM lock?"

"Maximum."

"Temperature sensor?"

"Check."

Thomas Adkinson swiveled toward his instrument panel, tuning out the inquisitional turn and counter-turn between the pilot and the engineer. His own board was green, the robot arms fixed to the underside of the Marble prepped and ready to go.

The series of echoing booms from outside the hull had ceased, replaced by a faint swishing noise: the entry plate had been welded back into place, and all traces of the weld were now being polished away. A newcomer to the Drilling Complex, walking around the outside of the Marble, would see only a perfectly smooth sphere with no indication that three men were inside.

Three extremely cramped and uncomfortable men.

Adkinson shifted on his tiny metal chair, trying to find a position in which he could be comfortable for the next twenty-four hours. Because getting into and out of the Marble was so time-consuming-ninety minutes prepping for descent, thirty minutes for extraction afterward-the crews had to take what were essentially triple shifts for maximal efficiency.

Maximal efficiency, my ass. Christ, there had to be an easier way to earn a living.

The comm-link chirped. "Marble One, this is Dive Control," came the disembodied voice over the speaker. "Status?"

Grove, the pilot, took the mike. "This is Marble One. All systems nominal."

"Roger."

Adkinson snuck a look at Grove. As pilot, he was technically in charge of the dive, which was a joke because the guy had little to do other than watch a few gauges and make sure there were no screw-ups. The real work was done by himself and Horst, the engineer. Even so, Grove was the kind of guy who was always aware of the audio-video feed that was being transmitted not only back to the Drilling Complex, but to a secure base outside of Washington, as well. He had to act commanding for the camera…

The comm-link chirped again. "Marble One, water lock is open. You are cleared for descent."

"Roger that," said Grove.

For a moment, all was still. Then there was a sudden jerk as the Marble was swung away from its berth toward the water lock. This was followed by a gradual settling sensation, and then a sudden, short plummet as the clamps were released and the Marble dropped into the lock. There was a booming sound overhead as the pressure doors were sealed. Like all other sounds from the outside, it was strangely attenuated, echoing and reechoing faintly in a hundred crazy ways.