"T'hy'la, there is something something of great import I must speak to you about." The half-Vulcan first officer stepped into Kirk's quarters and immediately sank on the sofa.

Spock's grave voice made Kirk smile. He loved when his science officer got all serious like that. Since that happened pretty much every time Spock opened his mouth, Kirk had a lot to smile about.

"Lay it on me," he said, taking a seat next to the Vulcan and slinging an arm around his shoulder. "I'm here for you, baby."

Spock relaxed his habitual stiff posture enough to lean against his captain.

"It is… difficult for me to speak of this," he said to his clasped hands.

Kirk squeezed him closer to his side. Vulcans didn't generally appreciate such close physical contact and Jim felt justifiably gratified to know that he was one of very few humans who had ever been such close proximity to Spock outside the confines of hand-to-hand combat.

He slipped a knuckle under Spock's chin and tipped up his face.

"Spock," he whispered gently, "you know you can tell me anything."

*******

It was comforting to know that Jim accepted him for all that he was and did not try (well, not very hard, anyway) to make him something that he could not be. Once again, Spock realized how fortunate he was to have this man in life.

"There is much you do not know about Vulcans, Jim," he said. "I have kept things from you."

He felt a warm rush of pleasure and acceptance when Jim squeezed him again. He was very fortunate to have this man. He was immensely pleased he had not killed him after Jim had snuck back onto the Enterprise after being marooned on Delta Vega.

"You don't have to hide anything from me, Spock," Jim told him now. "What kind of a soul mate would I be if I couldn't keep your deepest secret?"

Spock's lips thinned as he debated the best way to tell his t'hy'la what was bothering him. It would not be an easy thing for Jim to hear; he risked losing everything they had gained over the past six months. And yet, if he failed to be totally honest now, he would certainly lose everything he had gained over the past twenty-eight years. Most specifically, he would lose his life.

He would have to be direct, he decided.

"The secret I must share with you is not solely my own," he murmured, staring deeply into Jim's ice-blue eyes. "It belongs to all of Vulcan and we do not even speak of it amongst ourselves."

He took a deep breath and turned away, afraid he could not continue. Jim's cool fingers grasped his chin again and moved his head back.

"Tell me, Spock," he whispered, his mouth just a hair's breadth away.

"Vulcan… biology is not like that of humans," Spock hedged.

Jim smiled radiantly and bumped his forehead against Spock's. The Vulcan caught his breath again. This was torture.

"Of course it's not!" the starship captain declared. "Bones grumbled so much that we're getting a brand new specialist in sick bay. Just for you."

"Dr. M'Benga will be unable to help me, Jim. This is not, strictly speaking, a medical matter."

Jim looked confused for a moment.

"But you said it was about biology…" His mouth dropped open and his eyes rounded and comprehension sank in. "Oh. You're talking about sex."

Silently, Spock nodded and stared at his hands again.

"I don't understand what the problem is."

"Jim, I did not mean to mislead you; I do not refer simply to intercourse," Spock began to explain. "The Pon farr is a mating drive that separates Vulcans from their logic, unleashing the passions we spend our entire lives holding in check."

"I still don't see the problem, Spock."

"Jim, if I do not mate during my Time, eventually I will develop plak tow and die."

Finally, Jim began to look concerned. Abruptly, he stood and began pacing around his quarters.

"Mate or die, Spock? Isn't that a little harsh?"

"It is neither cruel nor kind; it is merely biology."

Just as suddenly as he had started walking back and forth, Jim stopped in front of Spock.

"Well, I can't have the best officer in the fleet dying of blueballs, can I?" Jim grasped both of Spock's hands and pulled him to his feet. "You need extra sex? Have to jack off in between? We'll get you through this, Spock. I promise."

"Jim," Spock said plaintively, "you do not understand. The Pon farr is a compulsion to mate. Ordinary sexual relations will not alter its course."

Jim froze at that and to Spock's extreme dismay, frowned. After his mother's death, Jim had become the most important human in his life. Spock did not like to displease him.

"You mean you have to actually have to try to make a kid?"

Once again, Spock nodded.

"My body must believe this is so," he said by way of explanation. "In anticipation of my Time, I have discontinued my contraceptive treatments."

Jim stroked his square jaw thoughtfully, gazing at nothing.

"So, you just need to screw a woman while there's no pharmacological barrier to your own fertility? You don't actually have to get her pregnant?"

"Pregnancy is not necessary."

Jim's smile was like Earth's sun coming out after a foggy San Francisco morning.

"No problem, then!" he exclaimed. "We'll just get you a woman for however long you need one, and that's that. We'll still get through this. No problem."

Spock hated knowing that his next words would take away his t'hy'la's smile again, but they had to be said.

"You do not understand, Jim," he said, his voice quiet in his shame. "In the absence of a marriage bond, it is helpful if there is an emotional attachment. It is not imperative, but it increases the likelihood of survival."

Jim didn't just frown this time. His scowl was fierce enough to rival one of Dr. McCoy's.

"No!" he growled, shutting his eyes and gritting his teeth. "No, Spock, not her. Anybody but her!"

*************

Author's Note: Please let me know if this is good enough to continue.

disclaimer: I do not own Star Trek and I am not making any money from this fanfic.