Moriarty Makes His Big Play Against the Twins in Part 1 of 'Watson's Finale

The last episode of Watson left off on a terrifying cliffhanger when Dr. Adam (Peter Mark Kendall) kissed his girlfriend Lauren (Amanda Crew), who we know was wearing lipstick tainted by Moriarty (Randall Park). That meant a sigh of relief when this week's episode opened with Dr. Stephens (Also PMK) and Dr. Adam investigating a bunker beneath the Holmes Clinic's new patient's apartment. They discovered a fridge full of black mold, which Adam also ingested because he wasn't wearing a mask. That was sure to have some mitigating consequences on whatever Moriarty had planned, but in the beginning, Adam seemed fine. That would soon not be the case.  

Meanwhile, John (Morris Chestnut) was so focused on a new article about the clinic that would help the team build their library of genetic mutations that he didn't realize Moriarty himself strolled right into the clinic. Ingrid (Eva Harlow) was very aware of who the stranger complaining of migraines was and immediately volunteered to help him. Secluded in a clinic exam room, Moriarty revealed he wanted Ingrid to sabotage John's latest project by pouring sugar packets into the samples, and then she "would be free."  

This latest project of John's appeared to be Moriarty's prime target, and Ingrid at least figured out who was manipulating her, though that didn't stop her from going through with the plan. Little did she know, Moriarty wasn't asking her to set back John's research by a few weeks, but was actually ensuring his master plan to take out Adam worked out. 

Things were going very wrong for the team when Shinwell (Ritchie Coster) finally showed up and confessed that Moriarty had been messing with his research. He had been staying away to figure out how to write a confession to give to John, but he returned early when he discovered the twins were sick. Only one man could get to both of them, and Shinwell knew that the jig was up. 

He tendered his resignation, and we saw Moriarty's revenge start to unfold as Shinwell returned to his car. A gnarly red rash had appeared on his neck, giving the impression that Shinwell wouldn't be around for much longer, either. Morarity moved quickly, and he was ruthless with every movement.  

John took a moment to process his best friend's betrayal and then tried to dismantle the clinic. They could not continue their work if Moriarty was copying their database and using it for potential mass murder. However, John had put together a loyal crew. Sasha (Ingla Schinglann), Ingrid, and Mary (Rochelle Aytes) all agreed to stay and help try to find a cure for the twins. 

Luckily for them, John had just the right idea to help. Unfortunately, Morarity had also thought of that plan and was two steps ahead.

Our poor Adams. It turned out that he had relapsed while Lauren was out of town, but that wasn't what made him sick. Stephens, at least, believed him and got the team working on the case to figure out an alternative reason for Adam's bizarre behavior. They had no choice but to believe Stephens when he soon fell ill with the same symptoms. 

The team was hard-pressed to figure out what could cause the twins' identical symptoms that were increasing in severity with each passing hour. They finally landed on herpes that must have jumped to their brain, but Shinwell's confession confirmed that Moriarty had made a super herpes designed specifically to take down the twins. 

Now, the team had to figure out a cure for the super virus and how to deliver it to the twins before it was too late. The pressure amped up when Adams fell into a coma, but John realized that his current research could be the key to saving the twins. And if you just said, "Uh-oh," to yourself, you're correct. That research was the same research that Moriarty asked Ingrid to sabotage at the beginning of the episode. 

John had been developing samples allowing the team to implant an enzyme that would cure the virus in the twins' brains. However, Ingrid poured sugar into all of the samples, essentially killing them. It would take weeks for Watson to grow more, and by that time, both of the twins, who by this point were both in comas, would be dead. 

Oh, just wait. It got worse. Ingrid was drowning in guilt over what she had done, realizing that Moriarty had already known those samples would be the only way to cure the twins. John was able to extract just enough viable samples from the remaining cultures to make a cure for one of the twins. The team would have to choose which one of them received it. 

Who are they going to choose? Adams has a book coming out and a fiancé waiting, so you could argue he has more to live for. However, Stephens just confessed his feelings for Sasha right before slipping into his coma, so there's a deeply personal reason for her to choose him over his brother. It's a moral conundrum that won't be solved until the season finale. It looks like Moriarty has the team in quite the pickle, and that's exactly where he wanted them. 

Part 2 of Watson Season 1's two-part finale premieres on Sunday, May 11, 2025, at 9 p.m. ET on CBS. Episodes are available to stream the next day on Paramount+. Season 2 is already greenlit for 2026.