Thank you to J. Rosemary Moss for being my beta. She issued a writer's challenge: Write a scene where Spock Prime meets the younger McCoy. Here's my attempt. I'm usually more comfortable writing for TOS...

He was hurting. McCoy knew it even before Jim had driven Spock to such a violent reaction. Despite the Vulcan's insistence on not having emotions, it was clearly a lie. The other Vulcans---and Spock himself---might try to blame his reaction on his human half, but McCoy knew better. Vulcans weren't deprived of emotions, they just suppressed them; burying them down deeply within themselves.

An entire planet destroyed, so many lives lost forever...

McCoy remembered what he had said to Jim when they had first met: "My wife left, took the whole planet with her and left me with only my bones."

It was that remark that had earned him his nickname: Bones. As much as he liked the name, which only Jim used, the comment that inspired it now left a sour taste in his mouth.

Jocelyn hadn't taken Earth away from him. McCoy understood that now. Nero showed him what losing a planet really felt like when it came to Vulcan-and had nearly done the same with Earth.

Perhaps it was a message from God.

You thought you had problems? Guess again, buddy.

That older Vulcan, Ambassador Spock---according to Jim, he was an older version of their Spock.

"Not only a different time, but a different universe as well," the elder Spock was trying to explain to McCoy. He had come to visit the doctor to give important information about Vulcan anatomy, given that McCoy was going to be treating at least one if not many more during the course of his career.

McCoy had brought the subject over to time travel, trying to understand how this had happened.

"I'll admit my initial thought was that I had simply been pulled into the past. However, as similar as things are to the way I remember them, there are also noticeable differences."

"Such as?"

"Your eyes."

"What about them?"

"The Leonard McCoy I knew had blue eyes. Your personality and mannerisms are pretty much identical though. And for another, my McCoy was also nicknamed 'Bones' by Jim Kirk. Except in his case, he was referring to 'sawbones,' an old-fashioned expression for doctor."

Oh, great. Did this mean that Old Spock(it was the easiest way for McCoy to keep him separate from the young commander turned first officer) knew about McCoy's comment to Jim?

"It was just an expression, and you were hung over at the time."

McCoy looked up, startled.

"Another similarity: your emotions are very easy to read."

McCoy looked away.

"How well did you get along with your version of me?" he asked, trying to change the subject.

"We fought quite often. Sometimes in anger, other times were more playful in nature. Crew mates would compare us to both a married couple and siblings. We managed to earn quite a reputation, to the point where some were surprised to see us when we got along."

McCoy chuckled a little. "Why did you fight?"

"At that point in my life I was not at peace with my mixed heritage. I tried to cling exclusively to my Vulcan half. This annoyed my McCoy, who was not shy in expressing his feelings, and who could not understand my refusal to do the same."

McCoy smirked. "Another similarity," he said.

"Indeed, he would try to get an emotional rise from me, with limited success."

"Sounds like something I would do," McCoy admitted. "But I sure as hell won't be bringing up the destruction of Vulcan with him, no matter how mad I get. There are some lines you just don't cross."

Old Spock nodded. "In the heat of the moment, my McCoy would sometimes 'cross the line', but he would always feel remorse, and apologize for it." A look of sadness flashed in those eyes.

McCoy quickly changed the subject. "So, Vulcan anatomy. I know your hearts are located where a human's liver would be and that you have green blood. What else do I need to know?"

Old Spock seemed to think for a moment. "We have a third eyelid, to protect our eyes from our sun... we're usually not aware of it. Much like you are not aware of your appendix." There was still that faraway look in his eyes, as if he were looking into another place and time.

Abruptly, the elder Vulcan seemed to return to the present, locking eyes with McCoy.

"Listen closely, this is very important. I do not know if the Spock of this universe has already been promised to T'Pring, or if so, she survived Vulcan's destruction. But in my universe, in my past, I entered pon farr."

"Pon what?" McCoy interrupted.

"Pon farr. It is the Vulcan mating cycle. During that time we must mate, or we will die. If we have been bonded with someone, it is only they we can mate with."

"Oh," McCoy said, blushing. "Okay, so you're worried about our Spock entering this phase. Well, if this T'Pring person didn't survive---"

"Your Spock can mate with another person."

"Well, he and Uhura certainly seem to be in a relationship. Wait, I saw them kissing in the turbo lift, does that mean---"

"No, Vulcans are capable of having sex whenever they desire. It is only during pon farr that it is a matter of life and death. In my past my silence nearly cost me my life. Jim forced me to tell him what was going on. When we got to Vulcan, T'Pring declared a challenge, naming Jim as her champion. She wanted out of the arranged marriage, having found another. Jim nearly died by my hands. It was only the quick thinking of our McCoy that saved us both."

"Fascinating," McCoy said, and this time the older Spock's eyes were twinkling with amusement.

"If your Spock is as similar to me as you are to my McCoy, then you should be prepared to hear that expression quite often."

He turned serious again. "There is something else I must share with you, from my time. A cure for xenopolycythemia."

"You guys found a cure?" McCoy leaped up. "That's wonderful! People usually die from that within a year."

"I know. Your counterpart contracted it. During a mission together, we came across the cure."

"How?"

"It is a long story."

That haunted look was starting to creep back into the old man's eyes again. Never had McCoy seen a more accurate display of the expression, "The eyes are the window to the soul."

"I have taken up enough of your time, Doctor. Ambassador Sarek and I need to meet to discuss where the surviving Vulcans should go from here. There is much rebuilding to be done."

"Hey look, I'm sorry if I upset you," McCoy said quickly. Just my luck to suffer from foot in mouth disease.

"You did not, McCoy," The elder Spock reassured him. "I hope you and my counterpart will become good friends, as I was with my McCoy. It was he and Jim whom I trusted more than anyone else on the crew."

McCoy nodded. "I'll try."

"It was McCoy whom I trusted to carry my katra."

"Katra, what's that?"

"Ask your Spock," was the reply.

Left alone, McCoy thought over his conversation with the old Vulcan, and of the changes caused by Nero.

The Spock of this universe seemed to be more willing to embrace his human heritage; having said that since Vulcan was destroyed Earth was his home now. Her people were his people, in addition to the surviving Vulcans.

McCoy did want to reach out to him. Spock was going to need all the friends he could get.

Besides, if Spock was more willing to embrace his human side, McCoy would not need to push him as much as his counterpart had...