The observation deck is quiet and empty, dimly lit at this late hour and offering no distraction save the glowing glimpse of starlight passing by at warp. The engine is a quiet rumble barely discernible through the soles of his boots, and Spock is grateful for the solitude. With the violent urges burning his blood, all he wants is to be alone. The abandoned observation deck seems a reasonable locale.
He's not quite surprised when Jim Kirk finds him there.
The captain reads him too well, despite the short span of months they've been aboard the Enterprise—likely didn't even require the computer's assistance to locate his wayward first officer. The affinity sets off something uneasy in Spock's chest, and he stoically refrains from making eye contact.
"Bones filled me in." Kirk stands at Spock's elbow and makes a point of staring out at the stars. He doesn't say it aloud, but Spock can almost hear the 'why didn't you tell me' echoing in the room's empty space.
"I do not wish to speak of this, Captain," Spock murmurs, and he closes his eyes to resist the urge to turn and look at the man.
"How many times do I have to tell you, Spock? Call me Jim."
Spock says nothing because he doesn't dare.
"Look, it's okay to be embarrassed," Kirk says, as if addressing some ashamed, human adolescent after his first wet dream. The cautious tone is irksome, and Spock feels frustrated anger settle into his skin beside the fever already pulsing there. It's difficult to maintain his calm composure when the need in his blood has had days upon days to strip away his logic and control.
"It is not that simple, Captain." His tone is clipped, more aggressive than he intends, and he hears Kirk give an irritated huff at Spock's stubborn use of his title.
"Computer," says Kirk, decisive and confident. "Seal observation deck, authorization Kirk-one-six-gamma." Spock's throat feels dry and raw as he swallows, as he cracks his eyes open to track Kirk's movements in his peripheral vision, until his captain is standing directly in front of him, refusing to be ignored.
"I need my first officer, Spock. My ship doesn't run right with you checked out like this. Whatever it is that's not so simple, you need to find a way to simplify it."
"Jim," Kirk insists, and then takes a step closer, dropping his voice to a quieter tone. "What do you need, Spock? You can take some leave time if you want—you and Uhura, as long as you need. A shuttle craft, drop you on the nearest planet, anything."
Spock forces his breathing steady, forces himself not to blush at the intruding kindness. It's all he can do not to snap that it's nobody's business, that this is his problem alone. Instead he latches on to the worried intent in Kirk's voice, his eyes dropping closed against the earnest expression that he can't bear to look at any longer, because it is his captain's business.
He keeps his eyes closed as he says, "While the offer is much appreciated, I fear that leave with Nyota will not resolve this problem."
"It won't… what? I thought. Spock, Bones said…" Kirk trails off, newly uncomfortable, and the air is all awkward questions between them. Spock should be the one to speak, to explain, but he's not strong enough to break into the tense, resounding silence.
"Spock, she's your girl."
"Yes," Spock confirms. "Or was, at any rate."
"She ditched you now?" Kirk sounds horrified at the idea, appalled and offended on Spock's behalf, and in other circumstances perhaps it would be endearing.
"She did not," Spock quietly corrects the misconception. "She was, however, unable to assist me in resolving this… problem."
Kirk is silent long enough that Spock suspects he's waiting for more information. Whatever McCoy explained, perhaps it wasn't enough to allow Kirk to infer the things Spock isn't saying.
"Look," Kirk finally says, and the sound of rustling fabric alerts Spock to the shift in his captain's stance. He imagines crossed arms, stubborn shoulders, as Kirk continues, "I'm sorry. I know you're uncomfortable talking about all this. But you're going to have to spell it out for me. You have to… Bones said you could die, Spock. Don't leave me in the dark when your life is on the line."
Spock braces himself as much as he can, because he knows the captain is right. Between his duty to the ship and his emerging friendship with the man, Spock knows he has no choice but to explain.
"It is not merely a question of physicality," Spock says, diving straight to the point now that he knows there's no way around it. "Pon Farr would not be deadly if it were a simple question of sexual release."
"Two minds," says Spock, and he imagines the comprehension slowly dawning across his captain's face. "Two minds joining as one. The mating bond is so much more than a mind meld, Captain. It is deeper. It is everything." Spock takes a steadying breath. "It is permanent."
"And Nyota wasn't willing to form this bond with you?" Kirk asks, close to comprehending.
"Nyota was willing but unable."
"Spock, look at me," says Kirk, and the concern in his voice is intense and palpable. Spock struggles to obey, but fear prevents him. The fear is illogical—what does he have to fear in the worried face of his captain? But still he dares not open his eyes, and his skin is on fire despite the chill of the room.
"Spock," Kirk insists, and the steel of command enters his voice. "Look at me. Don't make me order you to do it."
The command is enough to override the fear, and Spock finally forces himself to open his eyes and look. The sight hits him hard, low in the gut, and suddenly he knows why he was afraid. There's something dangerous uncurling in his belly, something dark and hungry and wanting, and it's all he can do not to reach out and touch. It's all he can do not to take, when it would be so easy. Kirk wouldn't stand a chance against him, and the thought chills and burns him to the core.
"This conversation was a mistake," Spock observes, his voice not quite even.
"Then it's too bad we're still having it. Tell me more, Spock. Tell me why Uhura can't help you. If she can't, there must be someone who can." For a split second Spock is terrified that Kirk will touch him—nothing but a reassuring hand on his shoulder or a pat on the arm, but all the contact it will take to rip away the last of Spock's crumbling defenses and leave him doing the unthinkable. Even without touching Kirk, Spock can feel it now: his captain's presence is intoxicating, and Spock feels raw potential in the air between them. He barely remembers to breathe.
He's silent so long that Kirk repeats his question: "Why can't Uhura help you?"
"It is not an equation set in stone. Between Vulcans, compatibility is highly probable. With other races it is… less so. It helps if there is an existing connection. I had thought, with Nyota…"
And just like that Spock can't bear to continue. He turns his back and clenches his hands into fists, drops his gaze and then presses his eyes tightly shut. He would run, but the deck is sealed by the captain's command code. There's no way Spock's getting out until Kirk himself decides this conversation is through, and even now Spock can feel the same stubborn gaze burning into his back.
Heavy footsteps, purposeful, until he knows without looking that Kirk is standing directly in his path, staring him down. As if Spock had any delusions that he could escape.
"Who can help you?" comes the question at last, gentle and damning.
Spock opens his eyes, lost and knowing it, and says, "You can."
Whatever response he expects the confession to earn him, the immediate acceptance that settles across Kirks' face is nothing like it. There's not a second's hesitation, not so much as an instant of doubt.
"What do I need to do?"
"Let me—" Spock chokes, and the fists at his sides tighten uselessly. "Let me…" But he doesn't know if he can put it into words. There are rituals, of course. Ancient Vulcan rituals steeped in history and myth, but Spock knows the only thing that matters is touch. The body welcoming as the mind opens to him, one and the same and perfect, and how does he explain to his captain—standing there and offering him everything—exactly what he needs? He stands frozen, lost, aching to touch and helpless to make the first move.
Kirk seems to intuit his need and takes a step forward. He rests a hand against Spock's chest—right where Spock's heart would be if he were human—his palm warm through the material of Spock's uniform. He might be about to speak, no way to be sure, but the dam breaks in that instant, and all at once Spock is moving.
He reaches out with both hands, one cupping the back of Kirk's head and the other finding the small of his back—uses the leverage to drag him into a deep, claiming kiss, and Spock groans at the welcome heat of his captain's body against him. Kirk's mouth is startled stillness beneath his own at first, and Spock's heart refuses to beat until those surprisingly soft lips part in compliant invitation.
Spock is breathing hard when he finally pulls away, when he presses his forehead to his captain's and feels the touch of Kirk's mind singing to him in promise. He loosens his hold, guilt and worry that he's being too rough, too demanding, too Vulcan when he knows the body in his hands is all too human.
"You don't have to be careful, Spock. I won't break." It's as if Kirk is reading his mind— and maybe he is. There's a connection forming between them, tentative and hopeful. Maybe Kirk can feel it.
And Spock knows the words are true. He's seen too many times already the levels of violence, of pain the man can take and keep fighting. Spock wants desperately to be stronger than this, but he isn't, and the reassurance rips away the last curtain of his resolve, letting the madness run him through.
He loses track of the next several minutes, blurred motion and the feel of fabric tearing in his hands, the heat of skin naked and overwhelming. His mind is on fire and reaching out, claiming and taking and forging something deep and strong between them. There's a wide bench at the periphery of the observation deck, black and smooth and cushioned, but they end up on the floor instead, right in the middle of the room where they started. His blood still burns hot in his veins, overwhelmed with his need for the flesh beneath his hands—for the heat surrounding him as he drives deep and hard into his captain's willing body. The torn remnants of two Starfleet uniforms lie scattered in every direction.
"Jim," he breathes, and this time the name feels perfect on his tongue. Kirk is hot and impossibly tight around him, making him groan with each eager thrust, and Kirk's breath comes in ragged gasps against Spock's skin. Somewhere in the back of Spock's mind he knows he must be hurting his captain—the hitching grunts don't exactly echo with pleasure—but there's reassurance in the fact that Kirk is hard against him, is rocking with every single thrust, thighs pressed tightly against Spock's sides. Even if Spock had it in him to stop he's not sure that he would.
He feels the surge of climax and for a moment doesn't know whose it is, their minds surging and pushing and tangling together in a warm rush of ecstasy. Maybe it's both of them, one mind and one body as their coupling completes, and Spock buries his face against his captain's throat as the sensations drag him under.
Spock is aware of little after that, for an impossibly long stretch of time. His limbs feel lax and boneless, useless to follow his commands, and his body shakes with aftershocks. Kirk is still and warm beneath him, fingers brushing carefully in soothing patterns along Spock's face, his neck, his cheekbones. He doesn't seem to be in any hurry to get up, but Spock recognizes the façade for what it is. Even if he didn't know how hard and uncomfortable the floor must be, he can feel through their settling bond that his captain is hurting, and the floor isn't helping matters.
It's nearly too much effort, but Spock braces his hands against the floor, shifting and propping himself up so that Kirk isn't bearing the whole of his weight. Kirk's eyes are wide and bright, his expression cautious but open.
"Do you require medical attention?" Spock asks—not the first words he would prefer to speak, but he needs to know. The question earns him a wry smile and a quirked eyebrow, but no answer to speak of. It's meant to let him off the hook, but Spock knows better. "I am quite serious," he insists. "Captain. Jim. I need to know if you are injured."
Maybe it's the somber tone of Spock's voice, or maybe it's the use of his first name, but Kirk's eyes shift to a more serious expression, quietly considering and no longer focused on anything in particular. Spock can tell he's assessing the damage, careful evaluation just like Spock has seen on a dozen disastrous away missions.
"No," he says at last, and the way he says it makes Spock believe him. That and the pulse of earnest truth he feels in the bond between them, offering a more tangible reassurance. "No, I think I'm good. Just… let's not do that again for awhile, okay?" The tone is teasing, but there's truth here too—an edge of trepidation lurking beneath the words.
"Very well," says Spock, then leans in for a softer kiss. This one is a promise, and he watches rapt as his captain's eyes drift closed, as Kirk accepts kiss and promise alike.
The floor is as cold and hard as Spock predicted when he finally climbs off of Kirk and sits up. He can feel the force of logic reasserting itself in his mind, the overpowering weight of his emotions finally ebbing back under his control. The new connection holds strong, and the solid pillar of Kirk's mind bolsters the steadiness Spock finally feels.
"Thank you," he says, knowing it can never be enough.
"Don't mention it." Kirk's movements are sore and careful as he sits up, and Spock finds his eyes momentarily riveted to the darkening array of bruises that mar human skin. It's all he can do to raise his gaze to meet his captain's, but there's an easy smile on Kirk's face as he says, "Now. What are we going to do about clothes?"