Sherlock waits to see where Moriarty will make his posthumous move. One mysterious case in particular baffles Scotland Yard but Sherlock is more interested in a seemingly trivial detail. Why is someone destroying busts of the late Prime Minister Margaret Thatcher? Is there a madman on the loose? Or is there a much darker purpose at work? Something with its roots deep in Mary Watson's past.
Did You Know?
At approximately 1:08:30, when John bumps into the mystery girl off the bus, the poster in the bus shelter is of Toby Jones
's character Culverton Smith who appears in the next episode (#4.2) as the main antagonist. See more
It's nearly impossible that the dead body of the young man in the car could go unnoticed for a week. Even in a closed-up vehicle (which would not be airtight), the horrible and unmistakable stench of decomposition would be obvious throughout a large radius within a few days, and would be unbearable even inside the house (and possible neighboring homes) well before a week had passed. See more
What you're about to see is classified beyond top secret. Is that quite clear? Don't minute any of this. Once beyond these walls, you must never speak of it. A D-notice has been slapped on the entire incident. Only those within this room, code-names Antarctica, Langdale, Porlock and Love, will ever know the whole truth. As far as everyone else is concerned, going to the Prime Minister and way beyond, Charles Augustus...
Are you tweeting?
During the end credits, several letters are colored red. When read sequentially, they spell out "The Six Napoleons", the title of the Arthur Conan Doyle story that this episode is loosely based around. See more
References The Exorcist
Sherlock Theme Song
Performed by David Arnold
and Michael Price See more