Episode 8 of "Watson" kicks off with our eponymous protagonist leading his team on an expedition to the nearby mall, in search of intriguing medical cases. However, their mission is abruptly halted by the unexpected arrival of Irene Adler. Her ties to Watson stretch back to their days with Sherlock, but her presence today is driven by a more personal concern: her son, Angus, is gravely ill.
Irene, who once garnered a notorious reputation as a scammer, insists that she has left those days behind. Back at the office, Shinwell greets her with a chillingly reserved demeanor, his skepticism evident as he doubts her transformation.
Watson, however, agrees to examine Angus. At first glance, he seems relatively fine, but suddenly, he drifts off and struggles to maintain his balance. Fate unfolds its intriguing twist: Angus is, in fact, Sherlock's son! This revelation explains Watson's natural inclination towards diagnosing and his swift rapport with the boy.
Armed with this knowledge, Watson strategically divides the team into two, tasking them with uncovering more clues and determining the precise ailment plaguing Angus. Derian takes it upon himself to question Irene about Angus' symptoms, revealing that his first episode occurred during a football game. Subsequently, we discover that Angus also experiences breathing difficulties during his sleep.
While assisting Watson in the lab, Angus proves to be a keen observer, aiding in the deduction that the hair Watson was scrutinizing under the microscope belongs to a dog, necessitating a re-examination the next day. Irene, grateful for Watson's help, permits Angus to stay with him for the night, given Watson's availability of a spare room. After a heartfelt conversation with the child, Watson is even more convinced that this young boy is indeed Sherlock's son.
Shinwell voices his apprehensions about forming an overly intimate bond with Angus, as the team diligently pursues locating Sherlock's brother, Mycroft. Watson insists that the surest path to confirming their suspicions lies in acquiring Sherlock's DNA for analysis, necessitating a strategy. He thus dispatches Shinwell to London on a mission to converse with Mycroft, entrusting him with a peculiar trinket amidst his dislike for Irene.
Elsewhere, Croft taps into his covert network to uncover disturbing news: Irene has recently been implicated in multiple charity fraud schemes. He infers that she is exploiting Angus's alleged illness for financial gain. Armed with this revelation, the team confronts Watson, only to find that he was already privy to the deceit. Watson had discerned that Angus's symptoms were a sham, orchestrated solely to obtain Sherlock's DNA – a revelation Shinwell conveys upon his return from London. That very DNA is then absconded with by Angus and Irene later that day.
Irene's master plan from the onset was to secure Sherlock's DNA, leading Watson on a wild goose chase. Fortunately, the team retains a chance at redemption, thanks to Shinwell's foresight in planting a tracking device on her. Watson manages to intercept Irene and Angus at the airport, where a startling truth unfolds: it is Irene who is terminally ill, not Angus. Battling incurable cancer, she is desperate to find even the slightest glimmer of hope for a cure. Irene had conceived of selling Sherlock's DNA to a wealthy accomplice, aiming ultimately to secure Angus's future once she is gone.
In spite of the deceit that had unfolded, Watson imparts to Irene a faint yet flickering beacon of hope. There exists a treatment center in Texas, a potential sanctuary that might wield the power to vanquish her cancer. She embraces this offer, her heart lightening as Watson solemnly vows to embrace Angus into his care should fate decree her departure. Moreover, amidst this tapestry of revelation, we uncover a stunning twist: Angus is not, in truth, Sherlock's progeny. The trinket that Shinwell had scavenged from Mycroft—an object imbued with mystery—turns out to be a ring, a cherished heirloom once adorned by Sherlock during a fateful confrontation that left his brother vanquished. As Watson shares an afternoon's respite with Shinwell, he无意中drops this ring into his whiskey, the metallic clang marking the poignant close of the episode, leaving a bittersweet aftertaste in the air.
