I have to admit that I’ve haven’t been loving this season’s episodes of Sherlock. I’m not sure if it’s because we’ve waited so long for a new season and I’ve been building up my anticipation for it. However, the first two dull episodes of this season have been building up towards this finale’s explosive end.
The episode starts off with a young girl on a plane who realizes that the oxygen masks have been deployed but everyone on the plane is unconscious. She hears a ringing cell phone and she picks it up, she hears Moriarty’s voice greet her.
Mycroft Holmes (Mark Gatiss) is home enjoying watching an old film when the film footage is disrupted by snippets of footage from his childhood and the words, “I’M BACK”. Alarmed, he tries to leave the room only to discover it is locked. He is forced to go through a hidden door and discovers that there are intruders in his home. Although he tries to defend himself, he finds that he is outnumbered and tries to run away but discover that all of his doors leading outside are locked. As panic sets in, Sherlock Holmes (Benedict Cumberbatch) and John Watson (Martin Freeman) appear to show that it was all a ploy to prove the existence of their sister, Eurus (Sian Brooke).
Back at Baker Street, Mycroft meets with the pair as their client. Sherlock demands to know why he doesn’t have any memory of their sister and Mycroft reveals that she was more brilliant than either of the Holmes brothers. Because she displayed disturbing behavior as a child, such as killing their dog, Redbeard, and setting their house on fire, she was taken away. It was believed that she died in another fire that she set but in fact, she has been contained at a maximum security facility called Sherrinford. In the previous episode, it was seen that she has been able to get out and posed as John’s therapist, a girl he flirted with on a bus and Sherlock’s client.
Just as Mycroft insists that there is no way she could have escaped, in comes a drone with the sound of Eurus singing a song carrying a powerful bomb. As it senses motion, they need to stay still in order not to set it off but as they make a plan to escape, the bomb blows up the flat as John and Sherlock jump out the windows.
At sea, Sherlock and John drop onto a boat by helicopter which takes them to Sherrinford. The island that is tightly guarded goes on red alert as soon as they hear of that the boat has reached shore. John and a fake looking captain are arrested. The prison governor believes that he has found out where Sherlock is and instructs his guard to keep watch over Eurus while handing over his security card. In fact, the person in disguise is Mycroft and he’s given Sherlock a pass to see his sister.
Sherlock goes to see his sister while Mycroft demands to review the psychiatric interview tapes done with her. Because of her ability to manipulate people, he forbade the prison from conducting interviews with her but they ignored his warning. Sherlock demands to know how she was able to escape the prison but she coaxes him to step closer to the glass. Upon stepping closer, he discovers that there is no glass there.
Mycroft learns that the prison governor has been under Eurus’ influence all along. Just as the alarm bells sound, John sees Moriarty flashes across the screen as he is knocked unconscious.
In a flashback, we learn that Jim Moriarty (Andrew Scott) was invited to the prison five years to speak with Eurus for five minutes, unsupervised, as a Christmas present. During that time, she had him record audio and video that has been haunting them.
John wakes up to discover that he, Mycroft, Sherlock and the prison governor have all been placed in a glass cell. The group gets a chance to talk with the girl on the plane before it is terminated by Eurus. She says that she’ll give them another opportunity to talk to the girl again if Sherlock has either Mycroft or John kill the prison governor. If not, the governor’s wife will die. John attempts to kill him at the governor’s behest but is unable to go through with it. In the end, the prison governor kills himself in an attempt to save his wife but those weren’t Eurus’ instructions so she kills the wife as well.
She opens a secret cell door leading to another room. With each room, the group is given a puzzle they must solve. Which brother committed murder or can Sherlock get Molly to tell him that she loves him? Each task is more agonizing than the next but with each new room, the group will have the opportunity to speak with the girl on the plane and hopefully save it from crashing into a city. In one of the last rooms, Sherlock must decide who is more important to him, his brother, Mycroft, or his best friend, John. He must shoot the one who is less important. Unable to decide Sherlock decides to take the gun to shoot himself, which is not what Eurus wanted, so she takes them out by tranquilizing the group.
Sherlock wakes up in another room to see that he’s been separate from the others. He reconnects with the girl on the phone and John wakes up chained to the bottom of a well. Realizing that the cell he’s in is a ruse, he pushes the wall to see that he’s been brought to Musgrave, his childhood home. Eurus challenges him to solve his first case in order to save John from the well that is now filling up with water and mocks him with her cryptic song. Eurus also reminds him that Redbeard was not their dog. Sherlock remembers that they couldn’t have a dog because of their father’s allergy and that Redbeard was a nickname for his best friend. At the same time, John discovers that the bones in the well with him belong to a child.
Sherlock deciphers the song and realizes that the girl on the plane is a metaphor for his lonely sister and goes to her old room to finally give her the love and attention he denied her as children. She reveals where John is and he is rescued.
Eurus is taken back into custody to Sherrinford and the two brothers tell their parents about their sister. Sherlock now visits Eurus to keep her company and play violin duets together.
Sherlock and John also return to Baker Street to repair the flat and John receives an anonymous DVD from his wife, Mary (Amanda Abbington), encouraging him to continue working with Sherlock. The next season may be its so I’m hoping it has a lot more action than this one but at least this last episode was very entertaining.