The BBC’sSherlockis one of the most successful modern adaptations of Sherlock Holmes, but its most dangerous villain was so smart that it backfired on the show and ruined it. Thestate of the rights to Sherlock Holmeshas allowed artists from many branches to make changes to Sir Arthur Conan Doyle’s characters and stories, either adding new characters, crafting new cases for the famous detective, or changing the time setting and place of the stories. Some of the most successful recent adaptations have opted to bring Holmes to the modern day, and among them is the BBC’sSherlock.
Created by Steven Moffat and Mark Gatiss,Sherlockbrought the detective (played by Benedict Cumberbatch) and company to modern-day London. As such,Sherlockmixed some of Conan Doyle’s casesand adapted them to modern technology and social issues, also making a couple of changes to the characters’ backstories and personalities.Sherlockhad a strong start with its first two seasons, but saw a decline in its final two, especially the fourth season, which saw the surprise introduction of the smartest villain, who ended up ruining the show.

Sherlock’s Biggest Mistake Was Eurus Holmes
Eurus Holmes Was Introduced In Sherlock Season 4
The main villain inSherlock’s first two seasons was Jim Moriarty (Andrew Scott), the modern adaptation of Holmes’ archenemy, Professor Moriarty. Moriarty killed himself at the end of season 2, and the subsequent seasons didn’t have an established villain, introducing different antagonists with their own motivations. However, at the end of the second-to-last episode of season 4,Sherlockmade the surprise introduction of the third Holmes sibling: Eurus Holmes(Sian Brooke), despite a lack of hints and references to her existence.
Eurus had been following John Watson (Martin Freeman), posing as a woman he briefly flirted with on the bus, as Faith Smith, and as John’s therapist. Eurus turned out to bethe smartest Holmes sibling, even more than Sherlock, though he still managed to outsmart her in the series finale – but before that, the show went through its lowest moment. Eurus was a criminal mastermind, and showed a lack of empathy and more from an early age, as she lured Sherlock’s childhood friend into a well and left him to die.

Eurus was sent to the maximum-security psychiatric prison of Sherrinfordafter burning down the Holmes family mansion, but she was so intelligent and strategic that she manipulated everyone there. This allowed her to leave Sherrinford and come back as she pleased, thanks to which she followed John around and turned Sherrinford into a trap for Sherlock, Mycroft (Gatiss), and John. The problem with that was thatnothing about her plan and its solution made sense, and Eurus’ introduction felt very out of place.
Sherlockcould have redeemed itself for what it did in its final two seasons with a strong ending, which wasn’t the case with Eurus.

A lot ofthings went wrong inSherlock’s third and fourth seasons, and they couldn’t match the quality of the first two seasons, but Eurus’ arrival only sank the show deeper.Sherlockcould have redeemed itself for what it did in its final two seasons with a strong ending, which wasn’t the case with Eurus and her nonsensical plan that left many plot holes.
The Reichenbach Fall Marked The Beginning Of Sherlock’s End
The Finale Of Sherlock Season 2 Was A Turning Point For The Show
Sherlockpeaked in the finale of its second season, which saw the biggest plot twist of the show (one that actually worked, of course). Titled “The Reichenbach Fall”, it saw Moriarty setting his plan to bring Sherlock down into motion, which culminated in a meeting on the roof of St. Bart’s Hospital. Moriarty had everything planned to push Sherlock into killing himself, but Sherlock found a flaw in his plan and thus a way out. However,Moriarty unexpectedly killed himself, so Sherlock had no choice but to do the same, and he jumped off the roof while John watched.
However, right at the end of the episode, it was revealed thatSherlock survived and faked his death, but season 3’s premiere episode failed to explain how he did it. This is what sankSherlock, and the show could never recover, and the way to do so would have been a strong ending, but that wasn’t possible when Eurus was thrown into the mix.
A Fifth Sherlock Season Could Redeem The Show (But Will It Happen?)
Sherlock Season 5 Would Be Very Beneficial
The only way thatSherlockcould be redeemed after its messy ending would be with a fifth season, which has been rumored for years. In 2014, Moffat revealed that he and Gatiss had been plotting a fifth season (viaThe Independent), but the decision to actually develop it was never announced. The main reasonSherlockseason 5 hasn’t happened is the schedules of Cumberbatch and Freeman, and at the time of writing, there are no signs of it happening, soSherlockis still missing its best chance at redemption.