Martin Freeman and Benedict Cumberbatch as John Watson and Sherlock Holmes in "Sherlock"
Martin Freeman and Benedict Cumberbatch as John Watson and Sherlock Holmes in "Sherlock"

“Sherlock” season 4 episode 3 might be its last ever. “The Final Problem” started off with a dreadful plane ride, continued with shocking twists and turns, and ended with lots of questions. The UK show’s season 4 finale is no doubt its most suspenseful yet.

Spoilers ahead for ‘Sherlock’ season 4 episode 3

“The Final Problem” was Sir Arthur Conan Doyle’s short story, in which he had Sherlock and Moriarty killed at the Reichenbach Falls after a final confrontation. The obvious assumption was to have Sherlock (Benedict Cumberbatch) die in the finale as well. However, he already did (and promptly returned) in season 2 episode 3 “The Reichenbach Fall,” and to kill him again would take away the unpredictability the show is known for.

“Sherlock” season 4 finale did not end with Sherlock’s death. It did feature a lot of heartbreaking scenes, but it otherwise ended with a relatively happy note. The episode was truly a family affair, with Sherlock, older brother Mycroft (Mark Gatiss) and honorary brother John Watson (Martin Freeman) solving riddles prepared by their youngest sister Eurus (Sian Moore). Even Mr and Mrs Holmes (played by Cumberbatch’s parents Timothy Carlton and Wanda Ventham) made an appearance.

‘The Final Problem’ spoilers and recap

The episode started with a child in a commercial aeroplane full of sleeping adults, including the pilot. Helpless, she couldn’t wake anyone up. She was able to speak to another person not in the plane when a mobile phone rang, only to discover it’s Moriarty’s voice on the other line.

In London, Sherlock and Watson, who was alive after it was revealed he was only shot with a tranquiliser last episode, used scare tactics to force a confession from Mycroft about Eurus, whom Sherlock couldn’t recall at all. As Mycroft explained, Sherlock, in an effort to protect himself from trauma, erased her from his memory when she killed their family dog, Redbeard. Only that Redbeard turned out not to be a pet, but a child, Sherlock’s childhood best friend.

Mycroft, as the eldest and perhaps already in his pre- or early teens at that time, had to live with the disturbing memory. He protected Sherlock from the trauma and took it upon himself to visit Eurus in psychiatric facility/prison Sherrinford. Mycroft told their parents that Eurus died in the facility after she started another fire (she set their ancestral home on fire before she was taken away). It was of course a lie meant to spare their parents from pain.

The Holmes were smart siblings who all had “the deduction thing,” as Watsons called it. Mycroft was a lot more than Sherlock. However, Eurus was described as an “era-defining genius beyond Newton.”

After surviving a blast from a motion-detecting grenade attached to a drone Eurus sent to Sherlock’s 221B apartment, Sherlock, Watson and Mycroft set out to Sherrinford. Sherlock sought out Eurus’ cell alone while the two fooled and schooled the security about the lax in their system.

The title character found his sister in an elaborate glass cell playing the violin. He demanded to know how she escaped from the facility and disguised herself as Faith Smith (“The Lying Detective”). Eurus instead beckoned him to touch the glass. He did and promptly discovered that there was no glass. She knocked him out while the staff apprehended Mycroft and Watson. Sherrinford’s warden was revealed to have been brainwashed by Eurus as well.

Cut to five years prior, Moriarty (Andrew Scott) landed from a helicopter to Sherrinford. Mycroft sent for him as a Christmas present to his sister, who wanted five minutes of unsupervised conversation with the season 2’s main villain. What they talked about during that brief time wasn’t elaborated, but five minutes was enough to have Eurus learn a lot about Sherlock and concoct whatever plan she had.

Watson, who was also knocked down by the guards, woke up to a cell similar to Eurus’ with Sherlock, Mycroft and the facility warden. They were then given psychological tortures and puzzles in each room they were allowed to go through. These include extracting an “I love you” from Molly Hooper (Louise Brealey), who was truly in love with Sherlock, shooting the warden dead to save his wife, and quickly figuring out who among a list of three suspects killed a man, all the while trying to help the child in the plane. The final puzzle was for Sherlock to choose between Mycroft and Watson to kill, which Sherlock refused to do, instead pointing out the gun at himself. Before he could pull the trigger, Eurus had him shot with a tranquiliser.

By the next time he awoke, he was in a cell, which turned out to be a makeshift room in front of his old family home. He was talking to both Watson, who was chained to the bottom of a well, and the little girl on the plane at the same time, trying to save them both. As Sherlock worked out after decoding Eurus’ childhood song and the rubbish dates on the graves, the little girl was actually Eurus, asking for Sherlock’s help in landing the plane. Eurus was in her old room at the burnt house the whole time.

Watson was saved by a helicopter and it turned out all right for everyone. Eurus was in a catatonic state, with Sherlock visiting her in her Sherrinford cell to play violin with her. Their parents were shocked to find out their daughter was still alive.

Apartment 221B was restored to its former glory, with Watson even adding the famous yellow smiley paint on the wall. Following watching Mary’s (Amanda Abbington) last video message to them, Watson and Sherlock continue to solve cases and raise Rosie, Watson and Mary’s daughter, together. Molly still visits and she still looks smitten with Sherlock, while Lestrade (Rupert Graves) still brings them cases to work on. Mrs Hudson (Una Stubbs) is of course 221B’s unmoving fixture.

Questions for ‘Sherlock’ season 4 finale

How did Eurus do all those things, play with her brothers’ and Watson’s minds, while in a catatonic state inside her childhood room? Was Moriarty reprogrammed by Eurus before the events of “The Reichenbach Falls”? Was “The Final Problem” the final “Sherlock” episode?

Never should it be said “Sherlock” is an easy show to decipher. Some viewers were even left fuming on social media after watching the somewhat baffling episode. To this, Gatiss (who is also co-creator) has a reply.

“Go and read a children’s book with hard pages if you don’t want to be challenged. We’re making the show we want to make. We don’t make it a certain way because fans are pressuring us,” he told the Daily Star.

Sian Moore’s chilling portrayal of the cleverest Holmes

While Cumberbatch, Freeman and Gatiss were quite spectacular in playing their respective roles, it was Moore who was quite the standout. Using only very few emotions, she brought out the most chilling villain to ever appear in the show to date.

And that’s saying a lot as most of the show’s villains appeared unbeatable during their time. From Moriarty and Irene Adler (Lara Pulver) to Charles Augustus Magnussen (Lars Mikkelsen), they all seemed a worthy match to Sherlock’s superior intellect. But Eurus is in a class of her own. As she’s been described, Eurus is “incandescent,” and was just perfectly portrayed by Moore.

‘Sherlock’ season 4 finale leaked online in Russia

Hours before “Sherlock” season 4 finale was due to air in the UK on Sunday, it was leaked online in Russia. The producers pleaded on social media with viewers not to spoil the episode for others. “The Final Problem” aired on BBC Australia.

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‘Sherlock’ season 4 episode 1 ‘The Lying Detective’ spoilers: Watson grieves Mary properly; Another Holmes finally emerges
‘Sherlock’ season 4 episode 1 recap/spoilers: ‘The Six Thatchers’ ends in heartbreak with character death, hope with a third Holmes brother