John Watson: Sherlock’s not your only brother. There’s another one, isn’t there?
Mycroft Holmes: No…
John Watson: Jesus! A secret brother. What is he, locked up in a tower, or something?
Mycroft Holmes (to John): The fact that I’m his brother changes absolutely nothing. It didn’t the last time, and I assure you, it won’t with… with Sherlock.
Mycroft Holmes: Everybody dies. It’s the one thing human beings can be relied upon to do. How can it still come as a surprise to people?
Mycroft Holmes: But remember this, brother mine, agents like Mary tend not to reach retirement age. They get retired in a pretty permanent sort of way.
Sherlock Holmes: Not on my watch.
Mycroft Holmes: Are you having a premonition, brother mine?
Sherlock Holmes: The world is woven from billions of lives, every strand crossing every other. What we call premonition is just movement of the web. If you could attenuate to every strand of quivering data, the future would be entirely calculable. As inevitable as mathematics.
Mycroft Holmes (looking at a screen): Why am I looking at this?
Sherlock Holmes: That’s her, John and Mary’s baby.
Mycroft Holmes: Oh, I see, yes. Looks very… fully functioning.
Sherlock Holmes: Is that really the best you can do?
Mycroft Holmes: Sorry, I’ve never been very good with them.
Sherlock Holmes: Babies?
Mycroft Holmes: Humans.
Mycroft Holmes (reading Sherlock’s tweets): “Back on Terra firma.”
Sherlock Holmes: Don’t read them out.
Mycroft Holmes: “Free as a bird.”
Sherlock Holmes: God, you’re such a spoilsport.
Mycroft Holmes: Will you take this matter seriously, Sherlock?
Sherlock Holmes: I am! What makes you think I’m not taking it seriously?
Mycroft Holmes: “#OhWhatABeautifulMorning”