Everyone watched Sherlock on New Year's Day, right? Of course you did, you've had two years to catch up with the last series. It was a brilliant episode, but alas! we were not told how Sherlock managed to survive a deadly plummet from a really tall building, his supposed mangled corpse crunching onto the pavement below, all witnessed by a traumatised John.
There is no mention at the beginning of the episode of a date, nor does there appear to be a date on the gravestone. This is a deliberate negation on the part of the writers, fooling us into believing that this is set in the present day. In reality, these events clearly take place in the year 3000, a year that we know a great deal about thanks to the experiences of the band Busted.
Busted state in their informative song that in the year 3000, "Not much has changed, but they live underwater". This is why we have been so easily fooled. Apart from the water, London looks like the familiar city we know today, with its tall buildings, traffic and tube network. Nothing would suggest that anything had changed.
If London was underwater, why wasn't everyone swimming? This is a tricky question to which I have no certain answer, but I would speculate that the event which caused London to be underwater occurred perhaps 700-800 years prior to the year 3000. Being British, the Londoners grumbled a bit but eventually learnt to live with the water, developing the ability to breathe underwater, as well as walk, talk and go about general business. Society soon forgot that it was living underwater at all, so similar did life become to before the event.
Three-year-old Sherlock was standing on the edge of the platform, listening to the vibrations of the metal train tracks to see if he could predict the precise time of the next train. Just as he had decided that the train would come in 3 minutes and 25 seconds, the voice of his older brother whispered menacingly in his ear: "Don't stand too close to the edge, little brother..."
A little pressure from Mycroft on Sherlock's right shoulder was enough to topple the boy over the edge. As screams of horror and alarm reverberated around him, little Sherlock instinctively put his arms out in front of him to cushion his fall...
...but the painful landing he anticipated never came. Instead, it seemed that the breaststroke motion he had made with his arms has propelled him upwards, so that his feet rested gently on the train track.
In the panic, nobody ever realised the significance of this action. But for Sherlock, it was a revelation that would save his life on countless occasions.
Q. Busted state in their song that they saw "Triple-breasted women swim around totally naked". How does this fit with your theory?
A. If you recall, this is the same band that describe how they seduced and ran away with their 33-year-old teacher - I think this song counts as ample evidence that the band is prone to exaggeration and boastfulness. The appearance of triple-breasted women does not gel with Busted's opinion that in the year 3000, "Not much has changed", and I think that we can therefore discount it. The same goes for the band's impression that in the year 3000 their single had "gone multi-platinum" and that they had "outsold Michael Jackson".
Q. Does "your great-great-great-granddaughter" appear at all in the Sherlock series?
A. As Busted do not embellish on the description of said female, other than that she's "pretty fine", it is difficult to say. One obvious candidate is Molly Hooper, although it is unclear as to whether Sherlock thinks her "pretty fine".
Busted image from youtube.com