It was written by Stephen Thompson and stars Benedict Cumberbatch as Sherlock Holmes, Martin Freeman as Dr John Watson, and Andrew Scott as Jim Moriarty.

Inspired by "The Final Problem" by Sir Arthur Conan Doyle, the episode follows Moriarty's plot to discredit and kill Sherlock Holmes, also heavily using elements from the film The Woman in Green.

The episode flashes back to three months earlier, with Sherlock receiving plaudits and gifts from various people for whom he has solved cases, along with much-unwanted media attention, especially for his recovery of a Turner painting of Reichenbach Falls.

Meanwhile, Moriarty uses his mobile phone to simultaneously break into the case where the Crown Jewels are kept, open the vault at the Bank of England and unlocking all the cells at Pentonville Prison.

After being acquitted, Moriarty visits Sherlock and explains that his break-in was a publicity stunt to show potential clients what he is capable of, adding, "I owe you a fall."

Meanwhile, John is summoned to see Mycroft, who explains that four professional assassins have moved into flats on Baker Street and asks him to watch out for Sherlock.

They find that Moriarty has created a fake identity, Richard Brook ("Reichen Bach" in German), an actor whom Sherlock supposedly paid to pose as a master criminal.

Leaving John, Sherlock contacts Molly Hooper, a pathologist at St. Bartholomew's Hospital, and admits that, contrary to her belief, he respects her and has always trusted her.

Claiming that he was always a fake and explaining this last phone call is his "note", Sherlock swan-dives off the roof of St. Bartholomew, as John looks on terrified from the street, thereby ensuring that Moriarty's true identity dies with him.

After being knocked to the ground by a cyclist, John stumbles over to watch, grief-stricken, as Sherlock's bloody corpse is carried away by hospital staff.

[4] Moriarty's attempt to destroy Holmes's reputation and lead him to committing suicide by jumping from a building also has similarities to The Woman in Green.

[8] The Guardian's Sam Wollaston praised Steve Thompson's writing, particularly how the episode was, at times "faithful to Sir ACD's The Final Problem, then it will wander, taking in mobile phone technology and computer hacking ...

"[3] Commenting upon the cliffhanger ending, The Independent's Tom Sutcliffe says "Moffat and his colleagues have written themselves into a hell of a hole with regards to the next series.

"[9] Chris Tilly, who reviewed the episode for IGN, gave it a score of 10/10, calling it "The grandstanding conclusion to the brilliant BBC series, packed to the rafters with smart dialogue, audacious plotting, stylish direction and some truly wonderful performances.

The memes included recurring phrases such as "I fight John Watson's war", "Moriarty was real" and, most prominently, "I believe in Sherlock Holmes", amongst others, the latter of which was used in-universe in "The Empty Hearse".