"You've got to go to sleep now."
"No, Sherlock, I do not." Mycroft did not raise his head, concealing his slight startle at his brother's voice coming from the - as he had thought - empty doorway. "I have work to do. This business in Tunisia is far more sensitive than you can possibly imagine." He looked up with an unpleasant smile - but Sherlock wasn't there.
"Oh, I can imagine quite a bit," Sherlock's voice floated through the room. "I can imagine a case that no one has even thought of yet. I can imagine a violin solo, playing out to a full auditorium. I can imagine, apparently," his voice soured, "a childhood pet which never existed at all." Mycroft could not conceal his wince. "What I cannot imagine is why you would knowingly be sick and still working eighteen hour days, rather than being home in bed."
"Not all of us have a doctor for a roommate," Mycroft called snidely. His throat was rather sore, but he would have to be far more compromised than he was now to lose an argument to his little brother!
"Oh, please," Sherlock snorted, the sound still coming through clearly from whatever source Mycroft irritatingly could not divine. "You could hire any doctor in the country, and they'd be there within the hour. No, you're here for some other reason."
"As I said, I have work to do." Mycroft lowered his head back to the folder, trying to study and memorise the contents. It would be far easier if the words would stop blurring before his eyes.
For a moment, Sherlock's voice did not come, and Mycroft thought that maybe for once that was enough.
It was not to be.
"You're feeling guilty about something!" Sherlock crowed triumphantly. "Unusual for you, you're never guilty. Must be something serious, then, not the usual diplomatic twaddle–"
Mycroft looked sharply up at the ceiling, barely noticing the headache the movement inspired. "That 'diplomatic twaddle' is what keeps our country functioning and at peace–"
"Yes, boring." Mycroft didn't need to see his brother to know the dismissive hand wave that would have come with that comment. "Something important, probably personal life, you don't have any friends, so it must be family–"
Mycroft stood up abruptly from his desk. "That is enough, Sherlock! I am going home, where I will go to bed. Goodnight." He gathered together his files to take home, then reconsidered. It appeared Sherlock was not just listening, but watching, in which case he would prefer not to encourage Sherlock's further attention. This was one matter he did not want looked into.
"Eurus!" Then, more slowly, "You feel guilty about Eurus. You think you should have done things differently."
"You can't think I handled it well!" Mycroft burst out. He took a deep breath. "We are not discussing this, Sherlock. I am going home." He walked over to the door and left his office, locking it behind him. Surely now Sherlock could no longer distract him. He could go home, take a night off from his files, and be back at work early the next morning. Perhaps the rest would be nice, and may even drive out the cold that seemed to have taken up painful residence just behind his eyes.
A sound came from one of the empty offices.
He stopped. His grip around the umbrella handle adjusted, ready to draw at any moment.
Sherlock appeared in the doorway.
Mycroft released his grip on the sword, posture changing from defence to his more customary irritation. "Might I expect your presence everywhere I go from now on, brother mine?" he asked with an acerbic edge.
Sherlock didn't bother responding. "We both know the uselessness of platitudes, so let's cut to the chase. Eurus is smarter than both of us. I would give you a moment to recover from that blow to your ego, but you've known this all along, so I won't bother."
"Sherlock–" Mycroft tried to interrupt, but Sherlock steamrollered over him, stepping into his personal space and forcing Mycroft to take a step back.
"She's a genius, and you locked her in a prison. She was bound to escape. You're an idiot for not knowing that, any child could have figured that out. You might have even been able to work out how. John could. What you couldn't have known was what she would do to us." Sherlock paused for a second, but Mycroft had no response.
"You didn't know, Mycroft. Guilt is useless."
It took a moment, but when Mycroft managed to speak, his voice was steady.
"Thank you, Sherlock." There was no response, but he hadn't expected one. "If you don't mind, I'll be going home now." He wound around Sherlock and continued walking. This time, there were no interruptions.
By the end of the hallway, he had recovered somewhat from the unexpected emotion of the evening – recovered enough, at least, to call out behind him, "However you managed to bug my office, I want it gone by morning!"
"Turnabout is fair play, Mycroft! You could use the practice!" Sherlock shouted down the hall.
Mycroft smirked. Childish as it may be, he did have a soft spot for their bickering banter. At last, normalcy had returned. "Then I'll have men sent around to Baker Street in the morning. I'm sure they'd be happy to install some equipment for me."
"I knew you were out of practice, I didn't think you'd forgotten entirely. Don't think you can do it yourself?" Mycroft could hear Sherlock's smug grin in his voice, but he was forgetting: Mycroft had not reached his mysterious but prestigious position for nothing.
"As you like, brother mine. I'll be there at seven o'clock sharp."
He closed the door on Sherlock's muffled cursing, smirking to himself. Big brother always has the last word, especially the one who knows his little brother is not a morning person.
Title comes from this quote: "It is unwise to be too sure of one's own wisdom. It is healthy to be reminded that the strongest might weaken and the wisest might err." ― Mahatma Gandhi