The Final Problem story
Sherlock and Watson – who had been shot with a tranquilizer by Eurus – trick Mycroft into acknowledging her existence. Eurus steps up her attacks on Sherlock, culminating in the bombing of his Baker Street apartment. Sherlock, Watson and Mycroft venture forth to Sherrinford, a maximum-security psychiatric facility where Eurus is housed. Although Mycroft is skeptical at the suggestion that she has escaped, the trio discover that Eurus has compromised the staff and controls the entire Sherrinford asylum. She subjects the trio to a series of ordeals, testing their morals by forcing them to choose which of her victims live and die and ultimately forcing Sherlock to confront the memory of "Redbeard", a childhood friend whose death set in motion events that saw Eurus incarcerated. Realising that she will continue to test him until someone he cares for dies, Sherlock tries to connect with her on an emotional level, offering her the love and relationship with a brother that she never had, and Eurus stands down. Sherlock and Watson return to the Baker Street apartment, where they find another message from Mary imploring them to stay together. A time lapse montage shows them rebuilding the Baker Street flat to its original lived-in form before meeting a series of unusual clients. The title matches the Doyle short story "The Final Problem", but the plot contains elements from the short stories "The Adventure of the Musgrave Ritual", "The Adventure of the Three Garridebs", and "The Adventure of the Gloria Scott".
11 total · 6 major · 3 minor
| Theme | Level | Motivation |
|---|---|---|
| black sheep | major | Eurus was the black sheep of the Holmes family. |
| brother and brother | major | Sherlock and his older brother Mycroft were pitted against their evil genius sister, Eurus. |
| brother and sister | major | The plot revolved around Sherlock encountering the evil genius sister, Eurus, that he didn't know he had. |
| choosing who dies and who lives | major | Eurus tested Sherlock's morals on multiple occasions by forcing him to choose between who lives and who dies among various people. In one example, Sherlock had to shoot dead one of his best friend Watson and his brother Mycroft or else a little girl would seemingly died in an airliner crash. |
| facing a genius adversary | major | The evil genius Eurus subjected Sherlock, Watson, and Mycroft to a series of ordeals, testing their morals by forcing them to choose which of her victims live and die and ultimately forcing Sherlock to confront the memory of "Redbeard", a childhood friend whose death set in motion events that saw Eurus incarcerated. |
| private investigator occupation | major | We saw Sherlock Holmes and Watson doing what they do best. |
| childhood trauma | minor | Sherlock was traumatized by the childhood memory of his sister Eurus having drown his dog. |
| master and pet | minor | Sherlock had some flashbacks to his seeming childhood dog Redbeard. |
| to tell the truth vs. to offer a comforting lie | minor | Mycroft told his parents that his derange sister Eurus was dead, rather than confront them the the troubling truth that she was being held a maximum-security psychiatric facility. |
| attitude of superiority | not | Unlike in other episodes in the series, here Sherlock checked his attitude and ego. |