Watson joined CBS' lineup in the 2025 TV schedule, following a team of doctor-detectives who work to crack medical mysteries that often seem unsolvable. While the series has shown restraint in too many ties to Sherlock Holmes stories on a weekly basis, the return of Randall Park as Moriarty took place just one week before the introduction of the newest take on Irene Adler. The character will be played by Counterpart's Whoopie Van Raam, and the episode description sheds some light on the conundrum that brings her to Dr. Watson.
And as it turns out, the conundrum doesn't concern her own health, but rather the health of her young son. The episode, which airs on CBS and streams next day with a Paramount+ subscription, is called "A Variant of Unknown Significance," and this is what to expect (per CBS):
Watson runs into brilliant con artist and an old friend of Sherlock Holmes, Irene Adler, when her son Angus is admitted to UHOP for temporary paralysis. The fellows help Watson after he grows fond of Angus and pursue various leads to find a cure to his illness.
It's not entirely clear if Watson had ever met Sherlock's "old friend" prior to the upcoming episode, but it does sound like he hasn't interacted with her young son before. The character's origin goes all the way back to Arthur Conan Doyle's writings in the late 19th century, and has been adapted in the past with examples including Rachel McAdams in 2009's Sherlock Holmes, Lara Pulver for the BBC's Sherlock opposite Benedict Cumberbatch, and Natalie Dormer (sort of) in CBS' Elementary. For what Whoopie Van Raam brings to the role, check out the first look photo below:
It's hard to gauge too much about this version of Irene Adler just based on one photo, and Watson creator Craig Sweeny previously working as an executive producer on Elementary certainly doesn't mean that Whoopie Van Raam's Irene Adler will be identical to Dormer from the earlier CBS show. Having a young son in the hospital will certainly be different! Check out Watson spending some time with young Angus:
Based on the promo for "A Variant of Unknown Significance," Irene's motivations may not be entirely altruistic, as it suggests that she could be making her son sick on purpose and creating the medical mystery intentionally. It's a safe bet that the biggest twist of the episode probably wasn't given away well before it airs on CBS, so I wouldn't count on learning her true motivations until she arrives in the next new episode.
So, be sure to tune in to CBS on Sunday, March 30 at 9 p.m. ET for this next round of Watson if you want to find out, following the latest installment of Justin Hartley's Tracker. You can also stream new episodes next day via Paramount+ as well as revisit any earlier installments courtesy of the streamer.