"Our current assignment of charting Sector 70.2 of this unexplored quadrant has been proceeding uneventfully -- so uneventfully that I've been resorting to simulated battle drills and abandonship exercises to keep up my crew's efficiency. Everyone is looking forward to our scheduled inspection and repair detail at Star Base 11, and most of the crew have requested leave. Morale is high -- partially because of the party planned for the evening we dock. The only members of my crew who aren't space happy are my Chief Medical Officer and my First Officer. Both have been remarkably quiet for the past two days. I haven't questioned either of them, but I intend to if this behavior continues."

The Enterprise, starship of the heavy cruiser class, glided serenely through space, unmindful of the excitement caused by her approaching overhaul at Star Base 11. Most of the crew, however, were polishing up assorted skills for the party. Lieutenant Sulu and Yeoman Phillips were giving an exhibition of fencing. The choral group was rehearsing some slightly raunchy -- and slightly true -- ballads about the Captain. (He was carefully remaining unaware of them.)

And the Little Theatre was staging H.M.S. Pinafore. The production was directed by Lieutenant Uhura, and Chief Engineer Scott, who had a fine baritone, was singing the part of Captain Corcoran. Kirk, Scotty and Uhura were discussing the operetta one afternoon at lunch, when McCoy joined them.

"Have a seat, Bones." Kirk took a determined bite from a large green salad and sipped his skim milk. "I'm going to turn into a rabbit if you keep putting me on these diets. And then I have to watch while Scotty gorges himself on Black Forest cake!"

The Chief Engineer swallowed and grinned. "A man's got t' keep up his strength if he's going t' work all day and then rehearse all night!"

"Actually, Captain," Uhura said, tapping a manicured nail thoughtfully against her dark cheek, "we ought to update the production a bit, don't you think? Rewrite Gilbert and Sullivan to make it more... contemporary. For instance, why not set the operetta aboard the Enterprise, and rename it? U.S.S. Enterprise has just as much ring as H.M.S. Pinafore. And then you could sing the Captain's part!"

Kirk chuckled, hummed a few bars, then broke into song. "And I'm never ever sick in space... " he warbled, innocent of key. Uhura and Scotty chimed in.

"What, never?"

"No, never!"

"What, never?"

Well... hardly ever..." Kirk broke off and grinned at McCoy. "What about it, Bones? Have I got a future in the opera? The singing idol of Star Fleet, huh?"

McCoy rolled his eyes. "In my professional opinion, you should've had your larynx removed at birth to prevent that possibility. As a starship Captain you'll get by. As a singer... sorry, Jim."

Kirk shook his head ruefully. "Another great career, nipped in the bud by lack of encouragement." He glanced at the chrono, stood up. "Got to get back to the bridge. Coming, Doctor?"

When they reached the relative privacy of the corridor, he asked casually, "What's up, Bones?"

McCoy shook his head and didn't answer. Instead he asked, "Do you remember a planet Sarpeidon we visited two years ago?"

The Captain gave him a sharp glance. "It took me weeks to get the smell of that medieval jail out of my nose. And that crazy old Mr. Atoz... What about it?"

Again the Doctor didn't answer. After a long pause, he queried, "Did Spock ever talk to you about what happened to us back there?"

"No, as I recall, both of you were pretty quiet about the whole experience. From the official report you logged, I gathered there was a woman back in that ice age who saved your lives. What was her name?"

McCoy hesitated. "Zarabeth. Have you seen Spock lately?"

"No. Should I have? He's been off-duty for the past 36 hours." Hazel eyes scanned the Doctor's face, concerned. "Sure you can't talk about it?"

McCoy avoided the steady gaze. "Nothing to talk about, Captain. I'll see you later."

Kirk stared at the empty corridor, tempted to follow and pursue the subject, but finally continued on his way. McCoy might not care to admit it, but he shared a certain kinship with Spock. If he didn't want to talk, he couldn't be persuaded.

The bridge was quiet and reassuring. Kirk dropped into his command chair, scanning the clipboard of reports, but one part of his mind was counting the minutes until Spock appeared for duty. The best First Officer in the fleet... yes, he was that, for sure. What could McCoy have been hinting at, harking back to Sarpeidon? And that woman? Was he talking about himself? Somehow, Kirk thought not. But Spock wouldn't get mixed up with a woman... at least he never had, except for Omicron Ceti III, and those spores... funny, he'd always thought there was something besides the damned spores working on the Vulcan... and of course, there was T'Pring... but that was different....

The Captain jerked to attention, mind racing. It was 1301, and Spock was one minute late for duty. Impossible! But the computer tie-in flashed confirmation beneath his fingers.

Behind Kirk, the bridge door hissed shut, and Spock was standing by the command chair, hands clasped behind his back.

"Mr. Spock, is anything wrong? You're late." The Captain's voice was quiet, concerned.

"I regret my tardiness, sir. It won't happen again." The Vulcan's eyes were distant as they fixed themselves on a point three centimeters above Kirk's left eyebrow.

Sighing inwardly, the Captain gave up, knowing from long experience that Spock would talk when he was ready -- if ever. He stood up and said formally, "You have the con, Mr. Spock. I'm due for an inspection of the hydroponics lab at 0815. Report anything unusual. This sector has been charted as having some good-sized radiation storms."

The Captain left the bridge, aware of a nagging prickle of disquiet at the back of his neck. Spock would have called it illogical -- Kirk called it a hunch.

Kirk continued to worry during the next three days, as Spock's and McCoy's silence continued. He took out his frustrations on the training android in the self-defense section of the gym.

He was relaxing in his cabin after one particularly strenuous workout, sprawled facedown across his bunk, reading. The volume was one of Kirk's own cherished bound books. "The kind of book you can hold in your hands," as Sam Cogley had put it. The lawyer had introduced him to the hobby of collecting "real" books, and Kirk had found this remarkably well-preserved copy of an old favorite in an antique shop on Canopus IV. He was absorbed in the adventures of Captain Nemo and the Nautilus when the door signal flashed.

"Come in," Kirk put the book back into its protective cover when the door slid open to reveal his First Officer. He waved an arm invitingly at a chair. "Sit down. Would you like some Saurian brandy?"

Spock shook his head at the brandy bottle, and Kirk poured a small shot for himself. He sat down opposite the Vulcan, cradling the snifter in his hands, and waited.

Spock hesitated for a long moment. "You've been expecting to see me."

The Captain nodded. When the Vulcan didn't continue, he said, "I've known something is wrong for several days. First McCoy clammed up, then you. I can tell it's serious. Want to talk about it?"

Spock looked away, absorbed in a painting of the Enterprise that hung on the opposite wall. Kirk had to strain to hear him. "I must request leave for an indeterminate amount of time. It is... a family matter."

The Captain took a slow sip of the brandy, and studied his friend. The Vulcan looked tired; there were new lines around his eyes, and an aura of disquiet had replaced the usual calm control. Kirk listened intently, waiting for Spock's next words, and was suddenly conscious of something subliminal seeping into his mind, touching, and for a moment he was feeling deep resolution, mixed with guilt and shame. He held his breath, trying to look inward, to focus... and the contact, if contact it was, and not his imagination, was gone.

Spock was staring at him. "Jim -- you're not telephathic, I know, but for a moment--"

"I know. I felt it too -- for a moment. Long enough to know that you're determined to go, and that the situation, whatever it is, is pretty bad. But you're going to have to tell me the rest in words, Spock."

"If I could, I would share this with you, Jim. But I am responsible for this... problem. I must solve it alone."

"Something tells me that you're going to attempt something really hazardous. Am I right?"

Spock looked down at his hands, repeated, "I must go alone. Please don't ask me to explain why."

Kirk leaned forward, gripped the Vulcan's shoulder, and shook it. "I don't know what the problem is, but I know why you won't tell me. You're concerned that if I find out how dangerous this project is, I'll insist on going with you. You're right. I am."

The First Officer shook his head, and his voice was hard. "I will not allow it. I can't take the responsibility for your life, too. I am going alone."

Kirk set the snifter down with a thump. "Dammit, Spock, you don't have to tell me anything if you don't want to, but you'll have to desert to get off this ship without me."

Spock's jaw tightened, and his eyes held anger. Kirk stared into those eyes unflinching, and wondered where in hell Spock was going. Obviously, McCoy knew more than he was telling -- Sarpeidon? But that planet doesn't exist in the present. It blew up. The present... and the past... the woman... and the face on the wall of the cave... Cave? Face?

Kirk straightened. The image in his mind was clear -- a Vulcan face painted on a cave wall -- nothing he'd ever seen before. "I got it that time, Spock. Call it empathy, telepathy, what you will, I know, now. This has to do with... biology, doesn't it?"

The Vulcan nodded mutely, then leaned his head in his hands. His voice was strained. "Yes. My barriers must be slipping, if I could broadcast that loudly. Of course, we've been mind-linked, but... I'm tired, that must be it...."

"Never mind the explanations. I know, and it doesn't matter how." Kirk looked at the Vulcan and breathed, "It's incredible... 5,000 years ago in that frozen hell..."

"Zarabeth bore my child." Spock finished for him.

They stared at each other for a long moment, and finally the Captain stirred. "Maybe there's another explanation. Maybe Zarabeth painted you. You can't be sure...."

"I am sure. The face on the wall shows unmistakable Vulcan characteristics, but it's not my face. The eyes are different. The hair is longer. The features are those of an adolescent, or not much older. There are other things. The artifacts found in the cave along with the paintings show a higher level of civilization than the evolving race in that hemisphere had yet achieved. Traces of worked metal -- a stone lamp that used animal fat. Anachronisms in that time period."

Kirk was convinced, but shook his head. "Tormenting yourself over a child that lived and died 5,000 years ago doesn't make sense. There's nothing you can do about it."

Spock looked at him calmly. "I am going back to get him."

The Captain didn't know what he'd been expecting, but it wasn't this. "But... Spock... how?" Even as he said the words, a sudden, still-painful memory bit at him. "All is as it once was... let me be your gateway...." He took another swallow and felt the brandy burn his throat. "The Guardian of Forever, you're going to use it to go back."

The Vulcan nodded.

"Spock, that planet's been declared off-limits, except for the archeological expedition. They won't let you get near it, let alone go through. To get permission to use the Guardian would take a lot of clout -- probably by someone the rank of a planetary governor, at least...." He thought for a second, then answered himself again. "T'Pau."

"A logical deduction, Captain."

Kirk thought of T'Pau, tiny, frail, ancient... but packing enough authority in one request to override a Star Fleet Admiral's orders. Yes, she had the clout, all right. Would she use it?

Kirk said as much. The First Officer looked grim. "She will intercede, when I tell her the reason. The family is all-important on Vulcan. Family loyalties overrule even planetary law. Vulcan is virtually governed by an oligarchy composed of several prominent families. Mine is one of them. And T'Pau will not let one of the family live and die alone, far from his people."

"I don't envy you your mission, Spock," the Captain shook his head. "I wouldn't want to have to explain this to her."

"I am not looking forward to it, I assure you. But it must be done. It's my duty." Spock stood up, hesitated. "I assume that my request for leave can be approved immediately? We can divert to Andros in the Antares system with a loss of only one hour and thirty-two point four minutes."

Kirk nodded and got to his feet. "It's settled. I'll have your leave request processed immediately. If we drop you off on Andros, you should be about a week getting to Vulcan.... Getting clearance and returning to Star Base 11 should take you about another ten days. Good thing we've got that overhaul coming up.... Yes, that'll work... I'll be ready to go when you return. With luck, we'll be back before the final inspection is finished. Well? What are you standing there for?"

"Captain, I must go alone -- I absolutely refuse--"

Kirk cut him off in mid-sentence. "It's settled. Blackmail, Mr. Spock. I don't go, you don't get leave. Simple as that."

"This could be hazardous.... I can't allow you to risk..."

"Quit arguing. And quit trying to wrap me in cotton. Humans may not be as strong as Vulcans, but that doesn't give you a right to tell me what I can and can't do. After all, who's in command here?" Kirk glanced at the chrono. "You've got forty-five minutes to get ready. I'll see you in two and a half weeks. Move!"

Spock found that he'd responded to the snap of that last order automatically, and was standing in the corridor looking at a closed door. He shook his head ruefully, and hurried off to pack.