“The Sign of Three” is not only the best episode of Sherlock so far, it may be the best episode of television I’ve ever seen, ever. Don’t get me wrong. I’m a huge fan of Breaking Bad, but while that series grips your throat, Sherlock grips your heart.

The emotion in this episode was honest and earned, never manipulative or mawkish. The funny parts were fall down funny; the central mystery was tightly plotted. It was joyous and bittersweet and thrilling and had profound things to say, great and small, about the characters and human nature.

This series always astonishes me how it goes the unexpected route. How many times have we seen the bitchy, jealous third wheel, especially when it’s a woman joining the friendship of two men? Sherlock said fuck that. Instead, Mary is warm, vivacious, accepting of both her husband and Sherlock Holmes. I think she feels so refreshing to me because…well, how many women do we see on TV that are just comfortable in their own skin? Countless times well-meaning writers create self-conscious Strong Women™ who act like a stilted checklist of traits (she can kickbox and wear heels and hack into a computer while making a sarcastic quip!) rather than believable, fleshed out characters with personality and emotion. Mary is just real. She is effortlessly confident - secure in herself and her relationship. The writers don't tell us she’s smart, charming and funny, they just show she is and hope we follow along.

But the advance in S3 has obviously been with Sherlock’s character. He has grown, but it’s been well-earned development. You can see the groundwork that was laid in S1 and S2 about his increasing emotional maturity, and now the dividends are paying off in S3. Sherlock is now unafraid to tell those in his life that he’s concerned for them (Mycroft), appreciates them (Molly), or loves them (John). The thing that got me the most with Sherlock’s best man speech is that, while he’s longing in some ways, he’s never been jealous. He loves John and likes Mary, and in his mind that’s a cause for joy. He’s expressed it in so many ways this season so far: Sherlock just wants his loved ones to be happy. It is essential to his own happiness.

Sherlock S3 is doing something I never expected. It’s changed the game by allowing Sherlock, the character, to change the game. It’s not the story of an anti-hero. It’s the story of becoming a hero. How? By accepting the differences in yourself and others; by realizing that being weird does not equal being bad; allowing others into your life and your heart; taking joy in your loved ones’ happiness; being there for those who are unhappy. To paraphrase Sherlock’s speech, some people solve crimes, some people save lives. But the puzzle is not the point. As Moffat and Gatiss have said, this is not a detective show. It’s a show about a detective.