Which Sherlock Universe Will Guy Ritchie's Young Sherlock Join—Robert Downey Jr. or Benedict Cumberbatch?

Guy Ritchie is doing Sherlock, but not the one you think. Amazon is launching a teen-Holmes origin story that ignores both the Robert Downey Jr. movies and the Benedict Cumberbatch series on purpose. New timeline, new tone, new everything.

What this one actually is

Ritchie is adapting Andy Lane's Young Sherlock Holmes novels, with Hero Fiennes Tiffin playing a 19-year-old Sherlock who has not yet met Baker Street, let alone grown the reputation. We meet him at Oxford in the 1870s, where a campus murder yanks the restless prodigy into his first real case. One crime becomes many threads, and those threads stretch well beyond the quad.

No crossovers, no winks, no shared universe

Prime Video is keeping this completely separate. There is no narrative bridge to the Downey films, no stealth cameo, and no continuity with the BBC's modern Sherlock. Cumberbatch's version remains its own contemporary adult story; this is a Victorian-era origin.

First look: friends before they become mortal enemies

First images (dropped December 9, 2025) show something you do not usually see: Sherlock and James Moriarty on the same side. Dónal Finn is playing a young Moriarty who starts as an Oxford acquaintance and, for now, an ally. We also get peeks at Colin Firth as someone with the very Guy Ritchie name of Sir Bucephalus Hodge, and Zine Tseng as Princess Gulun Shou'an, a scholar and martial artist who looks set to blow up Sherlock's neat little worldview.

Who is playing whom

• Hero Fiennes Tiffin as Sherlock Holmes: a rebellious 19-year-old Oxford student with raw, unrefined instincts
• Dónal Finn as James Moriarty: the future nemesis, seen here as a classmate and early confidant
• Zine Tseng as Princess Gulun Shou'an: a brilliant scholar and martial artist who becomes key to the investigation
• Joseph Fiennes as Silas Holmes: the adventurous father casting a long shadow over his sons
• Natascha McElhone as Cordelia Holmes: the artistic, exacting mother
• Max Irons as Mycroft Holmes: the older brother who is, as usual, three steps ahead
• Colin Firth as Sir Bucephalus Hodge: a powerful figure tied to the unfolding Oxford mystery
• Numan Acar as Esad: a pivotal player in the wider conspiracy
• Ravi Aujla as Kishmore Malik: connected to the broader investigation
• Simon Delaney as Detective Fitget: a local officer ensnared in the campus case
• Adam James as Dr. Charles Maltby: a medical voice amid academic intrigue
• Rachel Shelley as Mrs. Anna Tilcott: a key presence in the university world
• Ian Midlane in a supporting role

The setup

The official line keeps it clean: Sherlock is smart but undisciplined, and Oxford is about to spit him out. Then a murder lands in his lap, forcing him to prove that his messy instincts actually work. The case expands into a globe-trotting conspiracy, nudging him toward the legend we know long before anyone asks for 221B.

When to expect it

The first-look rollout pegs the series for 2026 on Prime Video. Some earlier copy still floats 2025, but the latest materials point to 2026.

The Sherlock comparison you are already thinking about

If we are talking book vibes, Downey's brawling, disguise-happy Holmes skews closer to Arthur Conan Doyle's scrappy original than Cumberbatch's ultra-slick modern machine. Cumberbatch's deduction fireworks are wildly fun, but the late runs of Sherlock dial the theatrics up past Doyle's more grounded logic. That said, the best part about Young Sherlock is that it is not chasing either legacy. Ritchie and Prime Video are clearly building their own lane from the ground up.

Bottom line: teen Holmes, Oxford murder, Moriarty as a friend (for now), and a stacked cast. It is a fresh start by design, and I am curious to see how far into the 1870s globe-trotting it goes once the case blows open.