Sherlock was sitting in his leather chair, immersed in his Mind Palace. He had started out trying to figure out a problem regarding one of his cases, which got him thinking about corpses, which led him to think about death.
He thought of his own death first.
Sherlock had a will, of course. He had made one when Elizabeth was born. And as a consulting detective, which was fairly dangerous, it was good to have made such arrangements. Sherlock wanted his body to be donated to science. And he wanted all his money to go to Elizabeth, which was a considerable sum by the way. His own parents hadn't even died yet, so he hadn't received his inheritance from them. Whatever the amount, it would immediately be placed into his savings account.
Needless to say, his daughter would be very comfortable and would never have to work a day in her life.
Those would be the technicalities of his death. Then he began to consider those he would be leaving behind.
To be perfectly honest, Sherlock didn't anticipate making it to 'old age'. He fully expected to go out in a blaze of glory, shot or stabbed by some criminal. Hopefully, he would be killed by a very interesting criminal. And then Elizabeth and John would catch his killer.
Sherlock hoped that he at least lived long enough to watch Elizabeth grow up. He wanted to walk her down the aisle someday, watch her have a family of her own. Sometimes, he even caught himself imagining two or three little rugrats running around the flat at Baker Street and calling him Grandpa.
Next he thought of Mycroft. The British Government would fall into chaos if Mycroft were to be assasinated. Sherlock supposed that he might miss Mycroft just a little. After all, who else was going to allow him to do illegal things without consequence? The next British Government might hate his guts, instead of constantly worrying about them.
Sherlock wondered briefly about the possibility of Mycroft making Elizabeth his heir. Mycroft certainly enjoyed teaching Elizabeth about what he did and how he managed it. Sherlock wondered if you could put a job in your will.
Speaking of, Mycroft had a lot of money as well. Sherlock knew that if Mycroft died before him, all that money was coming to him, and therefore eventually Elizabeth.
Really, that girl was going to be able to afford Buckingham Palace once they had both passed on.
Sherlock got to thinking about Lestrade's death next. He knew that he would miss the DI. Lestrade let Sherlock invade crime scenes, solve his cases, and use police resources pretty much whenever he wanted. The next DI might not be so kind.
God forbid it be Anderson or Donovan. Sherlock would never be allowed beyond the police tape ever again.
Molly's death came next.
If she died before him, whoever replaced her would probably ban him from Bart's. No one would lay out bodies for him to abuse in the name of science. Sherlock wouldn't be given access to the lab, chemicals, instruments, or body parts.
If Mrs. Hudson died, the thing he would miss most would be her tea. She made it almost as good as John did. Though she was constantly insisting that she wasn't their housekeeper, she always had a tray of warm tea and biscuits waiting for them when they got back in the evenings.
Sherlock hoped that John lived to be an old man. He deserved to. Sherlock would miss him if he died. He would miss his body parts being thrown out, someone complaining about his experiments, and having a doctor around.
John was a calming presence. John was Sherlock's best friend. He was the voice in his head that told him right and wrong. The little angel on his shoulder had John's face and bomber jacket.
Sherlock didn't even want to think about Elizabeth dying.
No parent should outlive their child. And Sherlock desperately hoped he wouldn't.
If Elizabeth were to die tomorrow, Sherlock wanted to bleed out today.
If Elizabeth were to die tonight, Sherlock wanted his heart to stop right now.
Thinking about the deaths of his friends and brother had been slightly depressing. But to even consider the death of his only child...
Elizabeth was Sherlock's whole life. Yes, John was his best friend. Yes, Lestrade provided the Work. Yes, Mrs. Hudson made tea. Yes, Molly gave him body parts. Yes, Mycroft made sure he was never thrown in jail. But Elizabeth was his. She was a part of him.
If she died, it would be like losing a part of himself. One he would never get back.
He would do everything in his power to ensure that she outlived him, even if it meant jumping in front of a bullet or leaping in the path of a knife. He didn't care.
Elizabeth made him better.
Since she had been born, he had never even considered touching drugs again. He still got bored, but he would never put her in that sort of danger.
Sherlock had made himself sad by thinking about death for so long.
He resurfaced out of his Mind Palace. At some point, Mycroft had shown up. He was sitting in John's armchair, and Elizabeth was talking to him from the couch.
"Little Brother, you should really be dressed. It is past three, and you may have a client at anytime. Pajamas do not give good first impressions." Sherlock ignored Mycroft.
He got up and went to the sofa. Sherlock laid down and put his head in Elizabeth's lap. She didn't say anything, she just started absentmindedly messing with his black curls.
Mycroft gave Sherlock a calculating stare, but the detective didn't care if Mycroft could see his sentiment. Mycroft would be one to talk anyways, what with how often he had been at Baker Street. And Sherlock happened to know that Mycroft 'kidnapped' Elizabeth at least every other day. Several diplomats, presidents, and princes had emailed Sherlock and told him what a lovely daughter he had and had he ever considered allowing her to study abroad. Sherlock didn't even recognize half the people that emailed him, not that he even knew they'd met Elizabeth.
"Anyways, King Muri was asking after you, Elizabeth," Mycroft said. "He told me to tell you that should you wish it, a room is always open for you at his palace. He would be very honored if you would visit."
"He just wants to set me up with Prince Raj," Elizabeth remarked. "But the Prince does have wonderful hair, I should coordinate that visit."
Sherlock couldn't see Elizabeth's face to see if he was kidding. Just in case, he said, "No. I need you for a case that weekend."