SPOILER ALERT: There are lots of spoilers below.
11. Series 2, Episode 2 (2012) – "The Hounds of Baskerville"
This episode just felt off right from the beginning. A manic Sherlock gets the episode off to a shaky start, then the story played out in an uneven way which eventually led to a mystery that felt empty. The worst episode of the series. We did get to see Watson really get fed up with Holmes though that made it worth it!
10. Series 4, Episode 1 (2017) – "The Six Thatchers"
Its a mess of an episode that has some interesting points but does not make sense, there's not really a case that comes together, and then it is solved with no explanation of how that happened. But it does have some very good Mary scenes, she always added pop to scenes, but then she dies. It kinda sucked.
9. Series 1, Episode 2 (2010) – "The Blind Banker"
This was a very intense story, a bit over the top at times, as Sherlock chased down what starts off as a bank mystery but he ends up in a tangle with the Chinese underworld. There's murder, circus performers, and flying arrows. And it has one of the definitive Sherlock arrogant quotes when he said this to one of Scotland Yard's young detectives, "This investigation would move alot more quickly if you would take my word as gospel." Overall, too much schlock with the Chinese circus villains lowers the episode's quality.
8. Series 2, Episode 3 (2012) – "The Reichenbach Fall"
An important episode in the series has Sherlock matched up again with Moriarty in a series of strange encounters that make the whole thing feel uneven, but interesting and tense. The police turn on Sherlock, he becomes a fugitive, and it all drives to quite a cliffhanger. For a Sherlock episode, this is high drama! It feels like a movie at times and a series finale at others.
7. Series 1, Episode 1 (2010) – "A Study in Pink"
The opening of the series only takes about 20 minutes to introduce us to the characters and show us the driving forces that are going to make this series unique: Sherlock's brilliance and attitude, Watson's unassuming nature combined this tough mindedness, the offbeat stories, the words showing on screen for texts and hints, the constant witty dialog, and the fantastic cinematography/editing to create the distinctive style. The first scene with Sherlock and Watson is a classic. With a decent run around for the plot and an episode that is pretty fun, the series got off to a great start in the first episode. If you don't like this episode, then don't bother watching the rest!
6. Special Episode (2016) – "The Abominable Bride"
With a big break between season 3 and 4 they made a speical episode airing on New Year's Day 2016. This starts right were the last episode of series 3 ended, with Sherlock in the plane that has just taken off from the airfield with Waston, Mrs. Watson, and Mycroft watching him leave. It is a strange episode with most of it happen in Vicoritan Times with Sherlock workign on an unsolved murder. Sherlock, and the plot, bounce back and forth between the present day and the past as Sherlock uses his mind to solve the past crime and to figure out if Moriarty is back. It is quite fun and witty and sets up series 4 well.
5. Series 3, Episode 3 (2014) – "His Last Vow"
There's two things we learn at the start of the episode: First, what a bad ass Watson is when he takes on an addict in a drug house. Second, that Sherlock has a girlfriend! Its a very long episode with some twist and turns and quite an ending. The Watson's marriage has some real issues, Sherlock gets shot and then there's a few twists here and there. A very satisfying, complicated episode that leaves you wanting more right at the end.
4. Series 1, Episode 3 (2010) – "The Great Game"
An intense episode has Sherlock chasing around someone who straps bombs to people and then has them call Sherlock with hints. It is a complex storyline with many different threads and cases and ends with us meeting Moriarty for the first time. Moriarity's character is outrageous and unpredictable he adds a great edge to the series which is something that only Sherlock's inner turmoil had added up to that point.
3. Series 3, Episode 1 (2014) – "The Empty Hearse"
NOTE: There is a prequel to this episode you can watch on YouTube.
Sherlock reintroducing himself to his life after his "death" at the end of Series 2 makes for some of the best moments of the show to date. The first 30 minutes where we meet Watson's fiance and Sherlock drops in on them was fantastically witty, warm, and had that classic awkward Sherlock touch. The rest of the episode evolved around a case with terrorists which was good, but what made it fun was Sherlock, Watson, and Watson's new fiance getting familiar with each other again. And we get to see Sherlock's parents!
2. Series 2, Episode 1 (2012) – "A Scandal in Belgravia"
The episode begins with Sherlock and Moriarity ending their standoff with Moriarty departing with, "You'll be hearing from me, Sherlock." The next thing you know Sherlock and Watson are called to Buckingham Palace for his new case for the Royal Family. This leads Sherlock to an unforgettable meeting of dominatrix Irene Adler which includes much nakedness, the CIA, gay jokes, and a double cross. Adler makes quite an impression and creates a new vibe on the show with her "relationship" with Holmes. The whole scene in Adler's parlor is one of the best of the show. This episode feels a bit out of control with so many different things happening, but it is full of fun. Irene Adler should be in a every episode! Her appearance in any scene added intensity, intelligence, and wit.
1. Series 3, Episode 2 (2014) – "The Sign of Three"
This episode had a very different feel about than anything else so far. It was really focused more on Watson's wedding than the mystery that they stumbled upon during the wedding. Watson's fiance Mary is a great addition to the show as she goes with the flow, plays along with the wit, and adds a dash bit of lightness and fun to the whole thing. She makes you want to smile more when she is on the screen. While watching Sherlock, Watson, and Mary interact is lots of fun, the mystery isn't so great and the episode falls flat at times. Not their best, but maybe the funnest episode so far. And Sherlock flirts…. with a WOMAN!