Title: Differential

Author: Zane Gray ([email protected])

Series: Enterprise

Rating: Most of the story is PG, but expect some R-rated bumps along the way.

Summary: Commander Tucker and Sub-Commander T'Pol finally discover the path that Fate has chosen for them, even as perilous events unfold around them that could tear their fragile world apart forever.

About the Story: Differential explores the relationship between what I think are two of the most interesting characters in Star Trek in a long time. But there's a real plot here, with real drama and action. The events depicted in this story will have tremendous ramifications for all the characters and even, ultimately, for the relationship between Earth and Vulcan. The story fully respects the characters and situations as seen on the series through Season One (general first season knowledge is assumed). In terms of the timeline, it's set roughly a month after the events depicted in Shockwave, Parts I & II, but the continuity with the series diverges there. Differential is a sequel to three of my other stories, One Step Back, Two Steps Forward, Sympathies and Symmetries and Time Enough, and is a prequel to another, The Early Hours. Feedback is always welcome. Enjoy!



Prologue

The very early hours of the morning were Commander Charles Tucker's favorite time of day aboard the Enterprise. It was the middle of the starship's third watch, which meant that just over twenty people were on duty - the rest of the crew was probably asleep. Because of this, the ship's corridors were quiet in addition to being darkened to simulate night. When his own duty shift was over, and after having dinner in the Captain's Mess, spending an hour or so in the gym and attending to other personal odds and ends, Trip had gotten in the habit of walking the starship. It was his way of ending the day, making sure that everything was running smoothly and seeing to it that all was well - something that had become especially important to him after all the damage he and his Engineering staff had been repairing lately. Trip hadn't expected to become so attuned to the ship under his care in so short a time, but it had happened nonetheless. If something was wrong with the Enterprise, he could usually tell by its unique sounds and vibrations. As he walked in the quiet of the early morning, Trip could hear the low frequency hum of the ship's warp engines and feel its power through the deck plates beneath his feet. He normally found it soothing.

But on this particular morning, Trip's mind would not be soothed, absorbed as it was with his work. As part of his duties as Chief Engineer of Starfleet's first warp-capable starship, it was his responsibility to evaluate the efficiency of the ship's warp engines, and particularly to make recommendations on potential design improvements. No less than six other NX-class starships were in various stages of construction at the Warp Five Complex orbiting Mars. Of these, the Discovery was already undergoing warp trials. As the first ship off the line, Enterprise was an ongoing test platform in addition to its official duties, so Trip was in constant communication with Starfleet's Design Bureau. And with the first year of their deep space mission drawing to a close, he had a lengthy report to complete on the efficiency of the ship's systems.

With his mind occupied by intermix formulas, warp coil frequencies and subspace field dynamics, Trip had barely registered his walk. He'd already made his way down to E Deck, with just two decks left, and had passed Sickbay, the Mess Hall and his own quarters without noticing. He also failed to notice the sound of approaching footsteps.

"Good morning, Commander." Startled out of his reverie, he looked up to see Sub-Commander T'Pol walking alongside him. Damn Vulcan reflexes, he thought. Probably sneakin' up on me on purpose - tryin' ta throw me off balance. Hope I wasn't talkin' ta myself again...

"Hey, T'Pol. I'm surprised to see you up and around this early. Havin' trouble sleepin'?"

He was, as usual, annoyingly perceptive. T'Pol did her best not to react to this, raising only an eyebrow. "My mediation earlier this evening was... unproductive. I thought perhaps a walk would help."

A look of genuine concern crossed Trip's face. "Anything you wanna talk about?"

Taken aback, T'Pol was silent for a long moment, as she contemplated telling this Human what was troubling her. She had confided in Commander Tucker in the past, and he'd proven both trustworthy and discreet. They had even become actual friends recently - a relationship she found enjoyable. But the source of her problem was... complicated. She found that she lacked the energy the conversation would require. "Thank you, but no. What about you? When I approached, you appeared to be deep in thought. Are you also suffering from insomnia?"

Trip smiled easily. "Yeah, you could say that. I've been working on that big systems report for Starfleet, and there's this problem I'm trying to figure out." Then an idea occurred to him. "Long as you're awake, are you up for a challenge?"

T'Pol's expressions were subtle, but Trip was getting better at reading them all the time. This one could only be called skeptical. "If you are referring to an argument, Commander, I shall endeavor to return your insulting remarks with vigor despite the early hour."

Trip laughed out loud at this, earning another raised eyebrow from his companion. "No, that's not what I meant. I was actually hoping to run something by you... get your opinion on things."

T'Pol considered his offer thoughtfully. Truth be told, sleep was unlikely to come and there was nothing like a problem to focus one's mind. "I would be glad to assist in any way I can."

"Atta girl..." With an acre-wide smile, Trip led them back toward Engineering.


...


A short time later, Trip stood in front of the small beverage maker in his office, waiting for the device to issue a pair of drinks - strong black coffee for himself and green tea with a touch of mint for T'Pol. Then, steaming mugs in hand, he returned to the work table, which was covered in PADDs and hard-copy printouts, never missing a beat in his narrative. "I first got the idea when that Xyrillian ship was leeching off our engines for a free ride home. Right now, all the coils in both our nacelles fire simultaneously to maintain the warp field, which requires a tremendous amount of energy."

T'Pol acknowledged, "A design extension of Vulcan craft, which use a single, circular nacelle of simultaneously firing field coils."

Trip nodded, continuing. "Right. But what if we only fired a single pair of coils atta time, one in each nacelle, starting forward and moving aft? They create the warp field, and then we milk the field for all it's worth before it decays. By then, the next set of coils has fired, in effect re-energizing the field. If we cycled the coils - thousands of times a second, rather than firing 'em all at once - the nacelles would consume energy much more efficiently. And there'd be far less wear on the coils themselves, extending their operational life expectancy."

T'Pol considered this carefully. "Would this not also reduce the drag coefficient of our warp field against the fabric of subspace?"

Trip looked at her in surprise. "I hadn't thought about that, but sure. It's possible."

T'Pol sipped her tea absently, carefully examining the simulation playing on the viewer in front of them. "It is a remarkably elegant solution to the problem of diminishing energy return. It might even yield a substantial increase in velocity. Has the approach been considered before?"

The Chief Engineer shook his head. "It was abandoned because Starfleet didn't have the kind of high resolution subspace field measurements you'd need to make it work. At least not at the time. But since you suggested that we start monitoring our warp field more closely after the Xyrillian incident, we've collected more than enough data."

T'Pol immediately saw where he was going. "One could conceivably calculate the most efficient coil firing frequencies and energy input formulas from this data."

Trip smiled conspiratorially from across the table. "Exactly! Which is kinda what I was hopin' the most annoyin' Vulcan I know could help me with."

She stared at him icily. "Unless I am mistaken, I am the only Vulcan you know."

Trip laughed. "Imagine that."

T'Pol would never admit that she derived a disproportionate amount of pleasure from her constant bickering with Commander Tucker. It would, of course, be considered illogical by Vulcan standards. It was true nonetheless. "I find it fascinating, Commander, that something of actual value may have resulted from our encounter with the Xyrillians. Other than your pregnancy, of course."

To her satisfaction, Trip's show of annoyance was immediate. "Hey! Didn't yer mama ever teach you ta play nice with others?"

T'Pol merely blinked stoically and turned her attention back to the viewer. But Trip could swear he saw a hint of amusement flicker over her angular features. If I ever meet the jackass who said Vulcans don't have a sense of humor, I'll sure as hell give 'em a piece of my mind...


...


Several hours later, Captain Jonathan Archer emerged from his quarters to begin the day, with Porthos following behind, tail wagging happily. After settling the beagle comfortably in his Ready Room - and sneaking him a tiny bit of cheddar against his better judgment - Archer stepped onto the Bridge to find Ensigns Sato and Mayweather already at their stations.

"Morning, Captain," Hoshi called cheerfully.

Archer smiled, settling into the Captain's chair. "Good morning. What's on our plate today, Travis?"

The young Helm officer turned back eagerly. "Not much, sir. We're at warp three, still on course for Rigel IV. Should be there by 0800 tomorrow. Malcolm reported that we passed a stellar nursery last night, and recommended that we give it a closer look on our return trip. Dr. Phlox has a couple new cases of the flu in Sickbay. The scanners show clear and all systems are running smoothly. That's pretty much it. Just the start of your average day in deep space."

Archer laughed at the young man's enthusiasm. "Between Suliban cold-warring and a visit to the thirty-first century, I'll take average in deep space any day. Have either of you seen Trip or T'Pol yet this morning?"

Hoshi and Travis exchanged a quick glance. Hoshi looked back at the Captain. "No, sir. But the Sub-Commander's due on the Bridge in a little while."

Archer thumbed the intercom on the armrest of his chair, calling Commander Tucker's quarters. "Archer to Tucker." There was no response. He tried T'Pol's quarters next. "Archer to T'Pol." Still nothing. "That's strange. Travis?"

The helmsman quickly ran an internal scan of the ship. "According to their personal locators, they're both in Engineering... in the Chief Engineer's Office."

Hoshi looked up from her console, amused. "Uh-oh... that can't be good. What do you suppose he did now?"

Archer laughed quietly, "Good question. I'd better get down there and break 'em up. Last I heard, Trip was still on thin ice with T'Pol for replacing all her meditation candles with those trick ones you can't blow out. The Bridge is all yours, Travis." The turbolift doors closed behind him to the sound of their laughter.

On the way down to Engineering, Archer mused silently over the unique relationship between his Science Officer and Chief Engineer. Their constant bickering had caused at lot of tension at first, but had quickly settled down to little more than a regular source of amusement for the senior staff. Though they wouldn't discuss it, the misunderstanding over T'Pol's encrypted messages had somehow broken the ice between the two. There was no denying that they certainly worked well together. In fact, the Captain was hard-pressed to name two other crew members who worked more efficiently. More than once on their undercover mission to observe the Akaali, he'd been surprised to notice them communicating with simple glances and gestures. Archer suspected that Trip had grown to like the Vulcan far more than he'd ever admit. T'Pol was the more difficult to read of the two, but he'd also noticed lately that the Vulcan tended to seek out his Chief Engineer's opinion on things more than anyone else's. They do say that opposites attract, Archer mused silently. Now why does that make me so damn nervous?


...


When he strode into Engineering a few minutes later, the Captain noticed that most of Trip's staff was already hard at work, even though the morning shift had yet to officially begin. He might come across as cavalier, but Trip certainly did run a tight ship. Nothing like a damn fine engineer - one of the best in Starfleet in fact - who was also the life of the party. It had been almost impossible for Archer not to become friends with Trip over the years, and the decision to chose the young man as Chief Engineer of the Enterprise had been an easy one.

As the Captain climbed down from the catwalk to the lower level, he could easily hear Trip's southern drawl booming from the open door to his office, despite the humming of the reactors. "Fer cryin' out loud, T'Pol! Ya can't even control the injectors at that temperature. They'd melt clean through the hull!"

The expected response was far calmer. "That is correct, Commander. But Vulcan plasma injectors are made of pure dikironium, which is capable of sustaining more than twice the required temperature. If we could fabricate a set of our own using dikironium or a proper analogue, we could..."

Archer paused in the doorway, clearing his throat pointedly to get their attention. "Don't tell me you two have been working down here all night?"

Trip and T'Pol looked up at Archer in surprise, then at each other. After a quick glance at the wall chronometer, Trip grinned at his Captain sheepishly. "Yeah... guess we sorta lost track of time. Sorry, T'Pol... didn't mean ta toss an all-nighter in yer lap."

For an amusing instant, the Vulcan glanced down at her lap in puzzlement. She recovered with admirable speed though - at least in Archer's opinion - and stood. "Not at all, Commander. I found our work to be quite... stimulating. If you will excuse me, I am due on the Bridge in thirteen minutes. Good morning, Captain." With that, she made a hasty exit.

Trip watched her departure silently, allowing her a measure of dignity. But he could barely contain the grin that was threatening to split his head wide open. When she was out of earshot, even for a Vulcan, Trip slapped his hand on the table and laughed aloud. Finally he stood and stretched his weary muscles. "Well... guess I'd better hit the shower, Capt'n. Gotta long day ahead."

But Archer wasn't about to let him off the hook that easily. "Stimulating, huh? I don't suppose I need to remind you of Starfleet's code of conduct among officers, do I?" His tone was one of amusement... but there was a slight edge of seriousness as well.

Trip feigned annoyance. "Oh, there ain't no damn regulation against funnin' and you know it! Now, don't get all mother hen on me. We were just working."

Archer relented, still clearly amused. "Whatever you say. You up for breakfast? I hear Chef's whipped up a stack of pancakes a kilometer high..."

As expected, the response was enthusiastic. "The higher the better! Gimmie fifteen minutes ta wash the stink off?"

Archer nodded with a smile and followed his Chief Engineer out. Yep... just the start of your average day in deep space.


--- Continued in Chapter One ---