"Why are you even asking me, brother? You know I despise Christmas. Especially after last year. I ended up nearly sending you on a suicide mission after you blew a man's brains out in front of witnesses." For some reason even Mycroft couldn't see, Sherlock wanted him to come to their parents for Christmas.
"First off," Sherlock said with barely controlled frustration. "It isn't a suicide mission if the person is forced to go. And the alternative would have been letting him use me to control you, as if I mattered enough for you to give in to him. He'd have let Mary's enemies know where she is. She'd have been killed, and the baby too. John would almost certainly have died protecting them."
"So you were willing to sacrifice everything for them? I've told you repeatedly that caring is not an advantage."
"My friendship with John Watson was the making of me," Sherlock insisted.
"The ruin of you, you mean. It made you go soft, and almost got you killed."
"So much for my loss would break your heart. John would have done the same for me. And I've learned something I hope you will someday. Caring and being cared about is an advantage, a very large one. If John didn't care about me, I'd be dead now. And if I hadn't cared enough about him to jump, Moriarty's snipers would have killed him. If Gilbert hadn't cared to give me work so I'd keep clean I might have overdosed by now. With my history with landlords, if it weren't for Mrs. Hudson I'd probably be homeless."
"Oh stop being so overdramatic! You'd have jumped regardless to defeat Moriarty, even with your fear of heights." Sherlock had fallen from a horse as a young child, and although me managed to get the resulting fear enough to cope, jumping was not something he'd been happy about. "As to getting clean, I would have had you committed to rehab before much longer. And do you really believe Mother and Father would let you die on the streets? You lived as a homeless man during your gap year even though they protested and you were fine."
"You're missing the point entirely. If you won't come for my sake, at least do it for our parents."
"Why are you even asking? You've never enjoyed my company. I hate Christmas. If you're planning on drugging everyone again someone has to remain alert. Better for everyone if I stay away."
"Maybe I'm asking because I'm trying to actually set things right between us. I've done my part towards that. You were the one that said the feud between us is childish and that people would suffer, but if you're not willing to try, maybe you should just stay away." By this point Sherlock was too angry to argue, and left with the door slamming behind him.
The door of Mycroft's office remained closed until it was almost time to go home. Anthea came in, a hopeful look on her face.
"Sir? I was hoping I could take some time away. It is Christmas, after all."
"Government work does not stop for Christmas. You know that. Every year you ask for time off and every year I tell you the same thing."
Her face fell, but she nodded and stepped back out.
Mycroft spent the rest of the evening that Christmas Eve enjoying a meal and reading before bed. Christmas Eve alone, the way it always was and exactly how he liked it. It was just another day. There were no carols playing, no fairy lights, and there was certainly no tree. His meal was professionally prepared, but nothing traditional for the season. It could just as easily have been August as December if it wasn't cold outside.
He was feeling a bit drowsy, nodding over his book. He was just about to put it away and go to sleep when he heard something from outside. Christmas carols? Yet it didn't sound like carolers. For one thing, there was an unearthly beauty to it, if Mycroft acknowledged things like beauty. For another thing, it seemed to be coming from right outside the window. That is to say, directly outside, not in the street. That window was on the second floor, and it had no balcony.
Mycroft would have gotten up to see what was causing the music, and why his security team had let whoever was behind it get so close, but soon there was no need. A strange light that somehow seemed to be made of every Christmas light that had ever been lit shone brightly and came into the room through the same window as the music. The carols faded out, and the figure of a man became through the lights.
"Alistair?"
The man's face was one Mycroft hadn't seen since he'd left uni. The closeness they had once shared was all but forgotten. It had been a long time since Mycroft had even spared a thought for him. He had heard Alistair had died, but he hadn't wanted the details. He was surprised at the feelings stirred when he heard the news, and did not want to feel anything close to caring. He was hallucinating. There was no doubt of that. Or more likely dreaming. There was nothing to cause a hallucination. The hallucination, dream, or whatever it was nodded.
"Merry Christmas, Mycroft." Mycroft rolled his eyes.
"If you are who you appear to be, you'd know how I feel about Christmas."
"That doesn't mean I can't wish you a Merry Christmas. As to how you feel about this season, I'm hoping to change that tonight. Myself and three others I should say."
"And what does it matter how I feel about Christmas? I'm far from the only person who doesn't celebrate it."
Alistair looked at him sadly. "You're missing so much, Mycroft, and you're heading down a path you'll regret."
"What I'm regretting is even bothering to talk to an illusion."
"I don't know how to convince you I'm really who I say I am. I could tell you about the ring you still wear, or things we've said."
"Of course a figment of my imagination would know personal details about me."
"I knew you would say that," he sighed. "Mycroft, I'm trying to help you."
"You always were a sentimental idiot, if you really are you. If you cared so much we wouldn't have parted on the terms we did."
"I told you the decision was yours."
"So why interfere now?"
"Because you're lonely and hurting, and you'll only be hurting worse if things don't change. I tried to help you when I was alive."
"Gave up on me, you mean."
The apparition shook his head. "You chose what happened, and if your heart were completely frozen it wouldn't still bother you."
"I never said that it did."
"Mycroft listen. I can't stay here long, but three others will visit you tonight. The first will come when the clock strokes one. Listen to their warnings. If you don't, you'll be in more pain than you can imagine. You can find what you need to change inside yourself. I know you can. Goodbye."
Before Mycroft could answer, the spirit vanished.