Prime Video's series Young Sherlock delves into the formative years of the iconic detective, introducing audiences to a younger Sherlock Holmes (Hero Fiennes Tiffin) as he navigates a murder investigation that brings him into the orbit of Oxford student James Moriarty (Dónal Finn). This intellectual duo, seemingly unstoppable, forms an intriguing partnership, though their moral compasses diverge significantly—Sherlock holding a strong code, while Moriarty operates with more fluidity. Adding another layer of complexity is Shou’an (Zine Tseng), an imposter princess with a determined mission, secrets that fuel Holmes family drama, and pervasive questions about loyalty, ensuring Sherlock’s hands are full.

A central theme explored in the series, and highlighted by co-stars Max Irons (Mycroft Holmes) and Zine Tseng, is the unique brotherhood between Mycroft and Sherlock. Max Irons elaborates on scenes around episode three, where Mycroft’s frustration with Sherlock’s anarchic nature and unconventional thinking becomes apparent, yet it is powerfully counterbalanced by a profound love and deep recognition of his younger brother’s unique and valuable intelligence. Irons suggests an understanding of Sherlock’s 'smidge of neurodiversity,' leading Mycroft to feel a protective instinct. Zine Tseng further emphasizes this bond, noting that whenever Sherlock asks for a favor, Mycroft invariably makes it happen, showcasing a sweet form of sibling devotion.

Mycroft’s intelligence, as described by Max Irons, aligns with Arthur Conan Doyle’s portrayal: a linear, logical, and perhaps even superior intellect to Sherlock's, but one that lacks Sherlock's distinctive gift for perception and perspective. While Mycroft might agree with the sentiment that his brother is 'the most interesting thing about him,' he brings his own strengths. Tseng asserts Mycroft's competence, suggesting that in a conventional academic setting, Mycroft would be an 'A student' while Sherlock might 'rank at the bottom.' Irons sees their contrasting intelligences as balancing forces, with Mycroft providing a refined counterweight to Sherlock's inherent chaos.

Zine Tseng’s character, Shou’an, receives an intriguing introduction, gradually revealing her complexities. Tseng enjoyed portraying Shou’an as a 'solar energy ball'—a character with immense drive and strong objectives who is 'making things happen' rather than merely exploring. Shou’an demonstrates remarkable strength and versatility, using various tools and weapons in her fight scenes, never sticking to just one, which Tseng found particularly enjoyable to embody.

The relationships between the characters are a core draw of Young Sherlock. While Sherlock and Moriarty share intellectual prowess, Shou’an and Sherlock develop undefined feelings for each other. Tseng confirms the presence of these mutual feelings, with Irons pointing to a specific dining hall scene where Shou’an watches Sherlock pick-pocketing with a 'real interest.' The series finale leaves these relationships, and the characters’ individual journeys, open-ended, generating anticipation for future seasons. Irons expresses a desire for Mycroft to continue his work within the system and government, maintaining his 'louche' demeanor as a counterpoint to the show’s more kinetic elements, and even jokes about a potential love interest to drag him into the dating game.

Key dramatic moments underscore the character dynamics. The intense Holmes family dinner scene in episode seven, where the family grapples with Beatrice, stood out to both actors. Tseng recalled feeling the palpable tension between the characters, describing Mycroft as 'strangled by both sides' and 'quite hopeless.' Irons found these table scenes particularly immersive, benefiting from the presence of 'actors of extremely high caliber' like Joseph Fiennes, Dónal Finn, Hero Fiennes Tiffin, and Natascha McElhone. Another memorable scene for Tseng was the emotionally charged moment in episode four where a noose is placed around Shou’an's neck, which, despite its dark nature, was described as 'fun' to shoot, especially when sharing a moment with Max Irons. Young Sherlock, with its intricate plot, compelling characters, and deep exploration of sibling and romantic bonds, offers a fresh perspective on the iconic detective's origins and is available to stream on Prime Video.