'Watson' Introduces Irene Adler & Mycroft in a Search for Sherlock DNA

Irene Adler is on the scene! The famous literary con artist, who has been played by such fan favorites as Natalie Dormer (Elementary), Lara Pulver (Sherlock), and Rachel McAdams (Sherlock Holmes), is taken on by Danish actor Whoopie Van Raam (most recently seen opposite Jason Statham in The Meg 2), made her first appearance in this week's Watson, and her reputation certainly preceded her. She, John (Morris Chestnut), and Shinwell (Ritchie Coster) had history when they all lived in London; however, now she's found herself in Pittsburgh seeking medical assistance for her son Angus (Sebastian Billingsley-Rodriguez).

This week's episode goes transatlantic, with Alder's ties to London forcing Sherlock to hunt down his older brother, Mycroft. Another significant addition from the canon to the series, Sherlock's older brother, Mycroft Holmes, has been played by actors like Mark Gatiss (Sherlock), Rhys Ifans (Elementary), and Sam Claflin (Enola Holmes). In Watson, he'll be played by Vincent Gale, who Americans will recognize from his turns on Snowpiercer and Midnight Mass.

Helping Irene and her son Angus was only a temporary distraction for John, who was still obsessed with having discovered that Moriarty (Randall Park) was still alive in last week's episode. The professor has been switching out John's meds, causing him to have hallucinations. John believes that his pharmacist is behind the switch, but he comes dangerously close to figuring out that Shinwell is also working for the professor. 

John completed his first examination of Angus and determined the young boy was having silent seizures. That's when Irene dropped the bomb that Angus is actually Sherlock Holmes' son. That changed the game for John and his fellows. He divided them into two teams. Lubbock and Adams were on the hopeful healers, set to investigate Angus' condition as if everything Irene told them was true. Ingrid and Stephens were the cynic squad, tasked with digging into Irene's DNA and sussing out any inconsistencies in her story. 

While the Hopeful Healers tried tracking down an old CIA contact, Ingrid was determined to win the investigation. She came up with a theory that Angus had FDIA, Factitious Disorder Imposed on Another, which until recently was known as Munchausen by Proxy Syndrome, which she confirmed by shoving Angus and watching him catch himself instead of falling on his face. His reflexes proved that he wasn't really suffering from muscular dystrophy and helped the team confirm that Irene was lying. 

John tasked himself with finding Sherlock Holmes's DNA so that they could run to compare it to Angus's (and confirm or refute Irene's story). He and Shinwell thought they had stumbled across a strand of the famed detective's hair on his old violin bow, but Angus was the one to realize it was the hair of Sherlock's old dog when he went to assist John in his lab. The hair may have been a bust, but Angus' detective work was all John needed to believe that he was talking to the son of his best friend. 

However, John's belief in the story did not negate the need for Holmes's DNA. Without a viable sample from Sherlock himself, he directed the team to hunt down Sherlock's brother, Mycroft. The search took Shinwell to London to consort with the reclusive brother, who handed over his DNA sample and asked to be told if "that parasite" (aka Irene) was lying. He would like to "make life inconvenient for her" if so. No one would accuse this Holmes brother of being soft, that's for sure. 

While Shinwell was abroad, John had Irene and Angus stay in his apartment. He caught Irene snooping in the middle of the night and pretended to buy her story that she was sleepwalking. The following day, he took Angus for a walk to "test his muscles," but really it was another way to test the boy's story. John found the inconsistencies and also concluded that Irene and Angus were lying, but not before Angus managed to steal the DNA sample that Mycroft had provided. 

Luckily, Shinwell was thinking ahead. He put a tracker with the DNA sample before Angus could steal it, allowing John to track Irene to the airport before she disappeared forever. John confronted her and revealed Irene's plan to deliver Sherlock's DNA to an Austrian oligarch who collected DNA of the world's smartest men for studying. Irene wanted the payout to support Angus because she has terminal cancer and only two or three years to live. John offered to give her an experimental treatment that would give her more time. The treatment would take Irene and Angus to Texas, and John promised to be the boy's guardian if the treatment didn't work.  

They parted on good terms. Irene even gave John back the DNA sample, which turned out to be Sherlock's blood on Mycroft's monogrammed ring after the two got in a fight years earlier. John soaked the ring in whiskey so the blood would evaporate and prevent anyone from stealing the genetic data of his best friend again. Something tells us that Moriarty may have something to say about that when he finds out. 

Watson continues Sundays at 9 p.m. ET on CBS. Episodes are available to stream the next day on Paramount+. Season 2 is greenlit for 2026.