“I’m not sure,” O’Herlihy admitted. “Possibly a stream of charged particles or directed plasma waves. Like a laser, almost.”

  Or a phaser? Kirk wondered. Actual phasers would not be developed by Earth science for at least two centuries. Had the probe fired some variety of phaser at Saturn? Spock had not detected any defensive systems aboard the probe, but perhaps its phaser banks operated on different principles and were not recognized by the Enterprise’s sensors. Or maybe the beams were simply a previously unknown type of directed energy. In either case, they would be beyond O’Herlihy’s experience.

  “So, the beams rebooted the hexagon somehow?” Fontana speculated, apparently more interested in their function than their nature. “Which stabilized the rings? That’s fantastic!”

  But not unheard of, Kirk thought. He recalled the alien hieroglyphics on the probe and that obelisk back on Miramanee’s world. Once activated, the obelisk had projected a powerful deflector beam that had kept the planet from being struck by an oncoming asteroid. Was it possible that the probe had been designed to serve a similar purpose, fixing Saturn’s deteriorating rings? Or, more likely, resetting some other mechanism hidden somewhere deep within the mysterious hexagon?

  “You may be on to something,” he told Fontana. “Perhaps the probe was here to repair Saturn’s rings.”

  “And it left once it completed its mission?” Marcus seized on the idea, visibly fascinated. “But who sent the probe? And what interest would they have in maintaining Saturn’s rings?”

  Good questions, Kirk thought. He wished he could tell O’Herlihy and Fontana more about the Preservers, not that there was much to tell. The ancient aliens were a mystery even in his own time. Had they anticipated humanity colonizing this solar system in the future and wanted to keep Saturn and its moons stabilized for Earth’s benefit? Or did they have another motive for fixing the ringed giant? Perhaps they simply wanted to preserve one of the sector’s natural wonders for conservation or aesthetic reasons. It would be funny, he mused, if the Preservers ultimately turned out to be some sort of cosmic park service.

  “Shaun,” O’Herlihy asked him, “you were out there when those pulses fired. What did you see before the probe shocked you?”

  You mean, what did Christopher see, Kirk thought, before I set up shop in his body. In truth, his last memory before finding himself in orbit was of touching the probe in the Enterprise’s transporter room. He hadn’t seen the pulses O’Herlihy was talking about.

  “To be honest, it’s all kind of a blur,” he said. “Sorry.”

  Marcus sighed. He sounded disappointed but not too surprised. “I was afraid of that. A little traumatic short-term-memory loss was to be expected, I suppose.”

  “Is that serious?” Fontana asked, sounding worried.

  “I doubt it,” the doctor said. “Patients who have been in accidents often have little recollection of the actual events. It’s probably nothing to be concerned about, provided the rest of Shaun’s memory is intact.” He looked Kirk over. “You do remember who I am, right?”

  He made it sound like a joke, but Kirk thought he heard something more serious underneath.

  “A nervous mother hen?” Kirk said with a grin. “Seriously, I admit I was a little shook up, but I’m feeling better every day. Stop treating me like a basket case, both of you. That’s an order.”

  “Fair enough,” O’Herlihy said. “But you’ll tell me if you’re having problems, right?”

  “You’ll be the first to know,” Kirk lied. He felt bad about deceiving the two astronauts. They deserved better. But he couldn’t risk changing history by revealing that he was actually a time traveler from the future. “But really, I just want to get back to work.”

  Fontana looked relieved. “Okay, that’s the Shaun Christopher I’m used to.”

  Kirk was glad to hear it. It occurred to him that if he had to impersonate a human of the twenty-first century, the commander of an exploratory space vessel was not a bad fit. He and Shaun probably had much in common, including similar instincts and training. Could be worse, he thought. I could be stuck in the body of an opera singer or a brain surgeon.

  When in doubt, maybe he just needed to act like himself.

  “On a lighter note,” O’Herlihy continued, “Mission Control also forwarded a new batch of personal e-mails from home. Not quite as good as a care package of homemade brownies, but they will have to do. There appear to be plenty of photos and videos to review at our so-called leisure.”

  Interesting, Kirk thought. He looked forward to studying Christopher’s correspondence in private. He hoped they would tell him more about Shaun as a person.

  Fontana flew down to the nearest computer terminal. “Duty be damned. I think we can take a few minutes out of our busy schedules to check out those e-mails right away.” She grinned at Kirk. “If that’s all right with you, Colonel.”

  “Indulge yourself, Commander.” He figured that Christopher would say the same. “After what we’ve been through the past few days, I think we can all use a little taste of home.”

  Too bad he wasn’t likely to have any messages from his real home.

  Or century.

  The crew members floated off to various terminals to enjoy their personal correspondence in relative privacy. Kirk was grateful that the other two astronauts were preoccupied with their own messages. That gave him a chance to skim Christopher’s messages without being watched too closely. He felt a twinge of guilt at reading Christopher’s e-mail but assumed that any assumption of privacy vanished when he took over the other man’s body. Besides, for all he knew, Shaun’s consciousness was residing at the back of his brain somewhere—if it hadn’t been erased or transferred elsewhere.

  Was Shaun about to read these letters, too? Kirk hoped not. He knew from experience how hellish it could be to remain aware but helpless while another mind controlled your body.

  I had enough of that on Platonius.

  Shoving the unpleasant memory aside, he checked out the first missive.

  “Hi, Dad!” the message began.

  Kirk blinked in surprise. Shaun had children? Not too surprising, considering the astronaut’s age, he realized, but the filial salutation still hit him like a phaser on stun. He scanned the e-mails quickly, trying to get his bearings. Shaun seemed to have three kids, two in college and one much younger.

  Color photos, attached to the letter, showed a Fourth of July picnic on a beach. The youngest boy, Rory, looked about eight years old.

  The same age as David, Kirk thought.

  Kirk had never met his own son. Carol preferred it that way. It dawned on Kirk that David—and his mother—would not be born for centuries. He found himself envying Shaun.

  “Mom is taking us to Colonial Williamsburg,” Rory wrote. “She says hi.”

  From the sound of things, Christopher’s kids were staying with their mom while he was in space. Kirk read the passage again. Just “hi” from the mom? He wondered what the story was with her and Shaun. Were they married, divorced, separated, or had they never lived together at all? Scrolling quickly through the e-mail, he didn’t find a separate note from the unnamed mother. The other letter appeared to be from Christopher’s sister—and his father.

  Kirk chuckled to himself. He couldn’t help being amused to receive a personal message from Shaun’s dad, retired Air Force Captain John Christopher. Only four years had passed, by Kirk’s reckoning, since he had bid farewell to Captain Christopher on the bridge of the Enterprise, but of course, decades had passed for Shaun’s father, who had not even conceived his son the last time Kirk saw him. And now Kirk was occupying Shaun’s body!

  Talk about a small universe, he thought. Or should that be a small space-time continuum?

  What were the odds that they would cross paths like this again, despite a gap of centuries? Kirk had to wonder if some cosmic intelligence was playing games with him, or was it just that time-travel conundrums were like some kind of persistent infection? Maybe o
nce you caught one, you were always susceptible to a relapse? Spock would surely have a theory on the subject, possibly involving temporal linkages or chroniton entanglement. McCoy would probably just chalk it up to a bizarre twist of fate.

  Maybe the truth was somewhere in between.

  Over at an adjacent terminal, Fontana looked up from her own correspondence. “How are the kids? They having a good time with Debbie this summer?”

  “Sounds like it.” Kirk wished he could pump Fontana for more details on Christopher’s family but changed the subject instead. “How about you? Any exciting news from home?”

  “Not unless you count my idiot brother breaking his ankle snowboarding. And my mom has a new gallery opening next weekend.” She snickered. “I told her I probably couldn’t make it.”

  “I suspect she understood,” Kirk said, relieved to be talking about anything other than Shaun Christopher’s mysterious loved ones. He resolved to scour the e-mail more thoroughly later for whatever personal info he could glean from it. “You’ll have to catch her next show.”

  He wondered if Fontana’s mom was a painter, a sculptor, or what.

  Watch out, he warned himself. Don’t let on that you don’t know.

  “I just hope she’s taking good care of Gus,” Fontana said. “God, I miss the little guy.”

  Wait. Fontana had a child, too?

  “Any message from him?” he asked.

  She looked puzzled by the question. “Last time I checked, bulldogs weren’t much on letter writing.”

  Damn, Kirk thought. I got it wrong again.

  “Well, you never know,” he said, trying to recover. “You can do wonders with dog training these days.”

  “Ha, ha, ha,” she said. “Very funny—not.”

  O’Herlihy sniffled over at the far terminal. His back was turned to the other astronauts. Kirk thought he heard the man choke back a sob.

  He seized on the distraction. “You all right, Doctor?”

  “I’m fine,” O’Herlihy insisted. He rotated to face them. “Just a little choked up, that’s all.” He wiped a tear from his eye and licked his finger to make sure it didn’t get away. “What can I say? I miss my family.”

  Kirk had already picked up on the fact that the doctor was a devoted family man. He had previously caught O’Herlihy mooning over home-video footage of a wife and a college-age daughter. They had looked like lovely women. He couldn’t blame O’Herlihy for missing them.

  “Nothing wrong with that,” Fontana said. “Every-thing okay with Jocelyn and Tera?”

  “They’re well,” he reported, although his hoarse voice betrayed how powerfully the letters from home had affected him. He made an effort to regain his composure. “My apologies. I shouldn’t get so emotional.”

  “Don’t be too hard on yourself,” Kirk said. “After all, you’re human, not Vul—” He started to say “Vulcan” but caught himself. “I mean, you’re only human.”

  “We all are,” Fontana added.

  “I know,” O’Herlihy said. He stared plaintively at the screen before him. “They just seem so far away sometimes. Like I’m never going to see them again.”

  Kirk tried to remember O’Herlihy’s biography but couldn’t bring up the details. He just remembered the name from the mission logs.

  “You will,” Fontana promised. “They’ll be there waiting for you when we get back.”

  And so will Christopher’s family, Kirk realized. They were millions of kilometers away now, but what about when he got to Earth? How in the world could he face Shaun’s own flesh and blood?

  He couldn’t even tell them what had become of the real Shaun.

  If he even still existed at all.

  Fifteen

  2270

  “Here comes another one!” Sulu blurted.

  A boulder-sized chunk of ice hurled toward the domed colony on the viewer. Between its size and its velocity, it had a good chance of breaching Skagway’s fading deflectors and maybe even the lunar habitat itself. A breach in the dome was a worst-case scenario that seemed to be growing more likely by the moment.

  “Got it,” Chekov said.

  Without waiting for a command to fire, Chekov unleashed a salvo of phaser beams that shattered the frozen meteoroid into hundreds of smaller fragments only moments before it would have slammed into Skagway. Vaporizing the object would have been cleaner, but they needed to conserve the phaser banks’ power. Pulverized ice crystals rained down on the besieged colony.

  Chekov let out a held breath. “That was a close one.”

  “Just like the last two,” Sulu commented. “Is it just me, or are these giant hailstones getting more and more frequent?”

  “Your perceptions are quite accurate, Lieutenant,” Spock stated from the captain’s chair. “The frequency of such near-collisions has increased by a factor of six-point-seven over the last twenty-four hours. As the rings continue to destabilize, ever more debris is being drawn toward Klondike VI, placing Skagway in jeopardy, even as the moon’s own orbit brings it steadily closer to the inner rings—where it will face additional hazards.”

  They were fighting a losing battle, Spock knew. Once Skagway entered the inner rings, the challenge of defending the colony would increase exponentially. And the Enterprise’s tractor beams, while state-of-the-art, were hardly sufficient to hold even a small moon in place.

  He called up the latest tracking data on Skagway’s orbit. The figures scrolled across the display panel on his right armrest. He performed the necessary calculations in his head. The analysis took only seconds.

  “Mr. Sulu.” He addressed the helmsman. “Skagway’s orbit has contracted by a factor of nine-point-two. Please adjust our own orbit to compensate.”

  “Already on it, sir,” Sulu said. “Matching course and speed.” He kept his gaze fixed on the wayward moon. “Don’t worry, Mr. Spock, I’m not letting those people out of sight.”

  Chekov sighed. “Too bad those drifting icebergs aren’t letting them alone, either.”

  Spock detected a note of fatigue in the ensign’s voice. By his calculations, Chekov had now been on duty for fourteen hours, twelve minutes, and forty-four seconds. A swift review of Chekov’s defensive phaser fire indicated a slight but significant loss in reaction time. Spock made a decision.

  “Lieutenant Ita,” he instructed, “please relieve Ensign Chekov at the nav station. Mr. Chekov, you are relieved.”

  “Sir?” Chekov looked back at him in dismay.

  “No criticism is intended, Ensign,” Spock assured him. Five years of working alongside humans had taught him the importance of taking their egos and emotions into account in command situations. Maintaining crew morale was not his forte, but he had learned that it was not a factor that could be safely overlooked, particularly where humans were concerned. “Your performance has been exemplary, but you, like all living organisms, are subject to fatigue. It is only logical to rotate key personnel as required. You may resume your duties after a suitable interval of rest.”

  “Well, when you put it that way.” Chekov grudgingly surrendered his seat to Maggie Ita. He yawned and stretched. “I suppose I could use a little break.”

  “Get some sleep,” Sulu urged his comrade. “You deserve it.”

  Sulu sounded faintly envious. Spock resolved to relieve the helmsman, too, once Ita settled into phaser duty. It would be inadvisable to replace both Sulu and Chekov at the same time, but Spock calculated that approximately thirty-six-point-five minutes would allow for a smooth turnover at the conn. Any sooner might compromise their defense of Skagway, while any longer might decrease Sulu’s efficiency beyond an acceptable margin.

  “Da.” Chekov trudged toward the turbolift. “I will be in my quarters if you need me.”

  “Thank you, Ensign,” Spock stated. “That will be all.”

  The turbolift doors closed on Chekov.

  “What about you, Mr. Spock?” Uhura asked from her station. “You’ve barely rested since the captain . . . was taken i
ll.”

  Spock appreciated her discretion. As planned, the reality of what had befallen Captain Kirk had not been shared with the entire crew. This, too, was a matter of maintaining morale. Only key officers had been made privy to the truth. As far as the rest of the crew was concerned, the captain had been temporarily incapacitated by his encounter with the alien probe and was now recuperating in sickbay. That seemed preferable to letting them know that James Kirk’s body was now occupied by a confused astronaut from twenty-first-century Earth and that the captain’s own mind was missing and presumed lost in the past.

  “Your concern is duly noted, Lieutenant,” he replied to Uhura, “but, with all due respect to Ensign Chekov, I am afraid that I’m not so easily replaced. Fortunately, my Vulcan heritage also grants me greater endurance and ability to concentrate in such circumstances.”

  Uhura did not sound convinced. “Are you sure that’s not just Vulcan pride speaking, Mr. Spock?”

  “Merely an objective statement of fact, Lieutenant.” He did not object to Uhura questioning him. He knew that she was only thinking of the best interests of himself and the ship and that she had never been afraid to speak her mind. “False modesty is not logical.”

  While accurate, his assertions did leave out certain qualifications. He had been in command of the Enterprise for precisely fifteen-point-six hours now, and fatigue was becoming an issue, even for him. Certain meditative techniques, along with the occasional bowl of plomeek soup, had helped to conserve his strength so far, but he could not maintain his focus indefinitely. Although he was reluctant to hand the bridge over to Lieutenant Commander Scott before the current crisis was resolved, especially since Mr. Scott was more usefully employed in Engineering, logic dictated that he eventually seek rest, too. He was half-human after all, even if he was loath to admit it.

  “Incoming!” Sulu warned.

  A trio of icy missiles threatened the colony. “I have them,” Ita reported. The slim Asian woman had recently transferred over from the U.S.S. Darrow. “Firing now.”

  Sapphire beams targeted the first two meteoroids, which blew apart into—relatively—harmless hail. She hastily attempted to blast the remaining missile, too, but it was accelerating too fast. The massive hailstone cratered into the spaceport outside the dome. A cloud of shattered ice erupted from the shattered landing pad.