explains

[Warning: The below contains MAJOR spoilers for Watson Season 2 Episode 10 “Never Been CRISPR’d.”]

What’s the bigger development in the Watson fall finale, which aired on Monday, December 15: The titular doctor’s (Morris Chestnut) discovery about Mary (Rochelle Aytes) and why he learns it, or the continued mystery surrounding Sherlock Holmes (Robert Carlyle)?

After seeing how far his patient Hobie (Nat Faxon) is willing to go for love and off his advice, Watson goes to tell the woman he loves how feels, and it’s not his girlfriend but instead his ex-wife Mary, However, instead, Watson walks in on her kissing her new beau (played by Aytes’ real-life husband, C.J. Lindsey). Meanwhile, Sherlock returns and shows some concerning symptoms that Ingrid (Eve Harlow), when Watson tells her of his friend, suggests could be a brain tumor. Watson seemingly gets him to agree to see a doctor, puts him an exam room … and returns to find him gone.

Below, showrunner Craig Sweeny breaks down the midseason finale, that ending with Watson and Mary, what’s going on with Sherlock (is he real?), and what’s to come when the series returns — in March and on a new night.

I had a feeling that Watson was going after Mary. But now she has a new significant other. What does that moment do to Watson, that he was ready to make that move and now he kind of has to grapple with the reality of that and what that means?

Craig Sweeny: I think it’s staggering to him, especially when you realize that — not that there would be anything wrong with being in love with the janitor, but he has walked in on a very viable candidate for Mary’s love there. It’s not just anybody. And so he’s forced to reckon with the consequences of dallying and waiting and that Mary has, in spite of their obvious chemistry, moved on in a pretty significant way.

How aware was Watson of his feelings for Mary before that point?

My opinion, he was pushing those feelings down pretty hard and that it was only the — obviously he respects Hobie. They have a sweet relationship, and I believe he was learning something about himself during that walk and before leaving that room, he would’ve guessed that he would’ve walked to Laila rather than Mary.

What can you say about this new relationship of Mary’s — for her? Forget about the Watson of it for a moment.

It’s somebody that you’d be happy to be partnered with. The actor is Rochelle’s real-life husband, which is fun. C.J., we know him just by virtue of getting to know each other on set, but he has a job that Watson, it is one of the few jobs in the world that he respects and is a little bit intimidated by. I wouldn’t even put it, adversary is not quite the right word because they’re grownups and certainly Mary’s partner hasn’t done anything wrong. However, Watson who faced down Moriarty and is Sherlock Holmes’ equal, is actually slightly in some ways intimidated by this guy.

So is this the beginning of the end for Watson and Laila, or is it kind of a matter of like, well, if I can’t be with Mary, I don’t want to lose everything?

Well, yes, he’s going to have to — The question Watson will face is, am I going to reckon honestly with the consequences of my choice right away, or am I going to try to walk a certain line or can I… I mean, even a character as noble as Watson can lie to himself and say, you know what, let’s just — who knows who was going to be in that conference room or however you justify it. So I think that he’s going to have to slowly reckon with, not immediately reckon with the consequences.

Then there’s the Sherlock of it. First of all, the handwriting for the messages — “Goodbye Watson” and the “Sherlock Holmes was here” on the wall, is that supposed to be from the same person?

Maybe.

I was comparing the two, and the Ses, Os, and Ws in particular look different. What can you say about what’s going on with Sherlock?

Yeah, I think that Watson — Sherlock has only been in three episodes of the season, but his behavior is growing more and more concerning to Watson. I think obviously if you look back at what’s been there, it would be reasonable to say that character has never been seen by anybody else, but there are also clues that indicate that he may be real. And so all of that will be — there is a consistent answer to all of it that is, well, to me, of course, not having written it all yet, I think surprising and satisfying. But I think one thing I might say is whatever you think about what’s going on with Sherlock, you’re at least partially right.

Sergei Bachlakov/CBS

While Watson and Sherlock were walking down the hall, I was trying so hard to track eye lines to see who people were looking at. But what can you say about your approach to the Sherlock scenes? Because there is this question of what exactly is going on. Is he real, is he not?

I think that Watson would like to, it’s one of the most meaningful relationships of his life, so he would like to believe and that Sherlock is back and Sherlock is real, and Sherlock is very eccentric. The things they experienced during the adventure of the cobalt fisher are real. And so that diagnosis is of genuine concern. Watson was also part of that adventure, so I think he’s not, you will see him get very quickly to sort of where I think a lot of the audience is right now, but he’s perhaps a little bit more used to Sherlock’s eccentricities and he’s reluctantly making his way towards the difficult truth.

These symptoms and the ones that he lists for Ingrid, she comes to this brain tumor diagnosis. Can you say whether or not whatever is going on, whoever these symptoms belong to, whoever this diagnosis is for, is brain tumor the right track?

I think we’re dealing with good doctors. I would say that, yeah.

What had you wanted to do with Watson this season in the immediate aftermath of dealing with Moriarty?

I/we wanted to tell a story about who this character is when dealing with the stuff of life rather than with a nemesis. I mean, I think when you have Moriarty, I was pleased with the story that we told about Moriarty, but I definitely didn’t want Season 2 of Watson to be like, and now this is the story of Gruner or Moran or that each season you have some villain lurking around the hospital in Pittsburgh. I wanted to tell a story about what’s meaningful in life to Watson, and that’s why love, friendship, his relationship with the fellows, it’s all —it is fun to explore it outside of the context of a fight with an adversary.

But could we see those villains you mentioned in future seasons?

Of course.

Talk about addressing mortality this season like you are.

I think writing a medical show is a little bit of a stakes cheat code because you’re wrestling with sickness and death every single episode. And so yes, it’s always tempted to put your characters through that as well, whether they’re sick or other characters may face question of mortality in other contexts this year.

This Pittsburgh mystery is intriguing. Is that something you’re going to be diving into when the show returns, or are you more so looking at the Sherlock of that part of it?

No, that’s going to be paid off in some way. Sherlock has a clear belief about what’s there in that room, and we will answer from the audience whether that’s true or whether it isn’t.

Speaking of that room, I love that abandoned wing. To me, it kind of feels like Watson’s version of Sherlock’s mind palace in a way, like your twist on it. Why did you want to introduce and show us this place that Watson is going to at this point in the series?

When I was thinking about the Season 2, I wanted a new spot. I wanted a private place for Watson. The city of Pittsburgh, which is my hometown, is full of these beautiful, forgotten spaces. There’s a lot of, at least in old, in terms of the United States, there’s a lot of old money that built Pittsburgh because it was once a steel town. So there are these beautiful spaces that have fallen into disrepair, and so it just felt like a natural place for Watson to go and think, and then for Watson and Sherlock to have scenes as well.

The character of Beck (Noah Mills) is so intriguing. I’m nervous about what he’s doing with Sasha (Inga Schlingmann), messing with her, those birth mother emails. Why did he narrow in on Sasha now? Or is he going through everyone at the clinic?

Well, I think that one of the things that’s true about people with Beck’s diagnosis, which obviously he shares to some degree with Ingrid, is a large ego that is easily wounded. And in the episode where Beck was in the clinic with them, when the character Fitz took over the place and forced them to treat his daughter, she wounded his ego in a pretty significant way. And I think he is not one to take that easily.

But we know that he was interested in the clinic before that. So is the way that he’s messing with Sasha kind of a side thing from his interest in the clinic or is that tied together?

I think it is a side thing. He was interested in the clinic as a potential profit center. I think Beck is definitely one who is looking for windfalls in his life for, I don’t know if you would say get rich quick, but he definitely was curious about what’s going on in the clinic. The clinic will still present financial opportunities to him in the back half of the season, just not in the way he was expecting when he first started sniffing around.

Is he a real threat, in a life-or-death way, to these doctors or is it more just the way that he’s messing with them?

I think Beck is very capable, more than any character we’ve met on the show, including Moriarty. I think Beck would stab you and kill you. Obviously the circumstances would have to be right. But yes, I think he’s a threat.

So Sasha says that whatever happened, she’s going to be fine. The longer that goes on, how long can that remain true?

I mean, if you believe you’re talking to your birth mother and you’re developing a relationship with that person, you are to me, by definition, making yourself vulnerable. I think that was perhaps a bit of wishful thinking on Sasha’s part.

I really like what you’ve been doing with Sasha and Stephens’ (Peter Mark Kendall) relationship in this first part of the season. What’s coming up there and what did you want to do with them up to this point?

I think we wanted to present a healthy relationship in its newer stages at a realistic pace and not artificially introduce drastic twists and turns. There’s plenty going on with Sasha and Stephens, in my opinion, in the first half of the season, but their relationship is presented as something that is just working for both of them. And even though Stevens is learning about his own diagnosis and Sasha has things going on as well, they’re happy with each other and they’re enjoying the glow of a new relationship and they’re having lots of sex like you’d hope to have with a new partner. So that’s an aspect of life that is wonderful when you’re lucky enough to be involved in it. And so we want to do that in a non-rushed way. We do start to present some challenges to that relationship in the second half of the season.

Colin Bentley/CBS

And that’s kind of in contrast to what’s going on with what we’re seeing with Adam.

Well, I mean, Adam has big challenges ahead. Adam is a Peter Pan figure who is about to have not one but three children at the same time. And so he’s really going to go through some big changes as he faces that reality.

Shinwell (Ritchie Coster) with a potential romance has been fun to see, as has him as a nursing student and what you’ve been doing with him there. Are we going to continue to see him growing in that way and building out a life that’s maybe not something that he thought he would ever have for himself given his past?

Yes. I think really good things have come into his life. I think that there’s an inherent kindness to that character in spite of the things that he’s done, but I don’t even know if, based on what we’ve seen, you can even call it a potential romance anymore, they’re definitely into something. And so yeah, you’re going to see him have to fight for the version of himself that he has right now as we advance through the season.

I love when we see Lestrade (Rachel Hayward). She’s just so fun. Are there any other Sherlock Holmes characters coming up this season?

I think we’re pretty full. We have this gallery where we’re trying to fight to get everybody in. I wouldn’t say we’re going to drop an arc with Henry Baskerville. It’s nice to have those characters out there and to be able to think about them, but we’re sort of playing in the sandboxing with the characters that we have.

What can you tease about the next time we see Sherlock?

Major advancements, clarity for Watson about the situation.

And what else can you tease about what’s coming up in the rest of the season?

I think that the season is about, as you’ve intuited, friendship and mortality, and you’re going to see major developments in the life of our main character, challenges that he wasn’t anticipating. It is about what happens — you can believe like, oh, I need to grow into the kind of person that’s worthy of the love I once had. But when chaos comes into your life, it presents a whole new set of challenges.

Watson, Midseason Return, Sunday, March 1, 2026, 10/9c, CBS