‘Young Sherlock’ Trailer: First Look at Hero Fiennes Tiffin & Colin Firth in Guy Ritchie’s Origin Story

Tanya Fedak December 18, 2025, 10:00 am

The Sherlock Holmes universe is about to get a little bigger, and now we have our first look at that expansion, as Prime Video has released the first teaser trailer (above) and images (below) for Young Sherlock, based on the best-selling book series by Andy Lane.

In this adaptation, the titular character is played by Hero Fiennes Tiffin, who is best known for his performance as Hardin Scott in the After trilogy and for his appearance as Young Voldemort in Harry Potter and the Half-Blood Prince. The series comes from Guy Ritchie, who directed the Robert Downey Jr. and Jude Law-led Sherlock Holmes films, and also stars Colin Firth.

The beloved detective has been reimagined across films and television, from Benedict Cumberbatch’s Sherlock TV series to Ritchie’s films. But this new adaptation will explore Holmes’ formative years and what pushed him to dedicate his life to solving mysteries, delving into more details than the 1985 adaptation of Young Sherlock Holmes.

“What we’re doing is recreating this character, but before we initially meet him, so it’s about getting the measurements right on how much of Sherlock to put in there and how many glimpses to put in of who Sherlock is going to become, because you want to see him,” Tiffin told Collider. “In any origin story, you want to see how they got to where they are.”

The series was filmed in Wales, and now the first-look photos, cast, and other details about the series are available. Here is everything we know about the Young Sherlock adaptation.

Hero Fiennes Tiffin_Dónal Finn_Zine Tseng (Photo credit_ Dan Smith)

Dan Smith / Prime Video

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**What is Young Sherlock about?**

Young, inexperienced, and unfiltered, the iconic detective will be reimagined for the Prime series. Based on Andy Lane’s Young Sherlock book series, the show will follow a 19-year-old Sherlock Holmes (Tiffin) as he navigates his first-ever case: an unsolved murder at Oxford University that puts his freedom at risk.

The official description for the show reads, “With all the wit and charm of Guy Ritchie’s Sherlock Holmes feature films, Young Sherlock follows the origin story of Sir Arthur Conan Doyle’s beloved detective in an explosive re-imagining of this iconic character’s early days. Sherlock Holmes is a disgraced young man – raw and unfiltered – when he finds himself wrapped up in a murder case that threatens his liberty. His first-ever case unravels a globe-trotting conspiracy that changes his life forever. Unfolding in 1870s Oxford and adventuring abroad, the series will expose the early antics of the anarchic adolescent who is yet to evolve into Baker Street’s most renowned resident.”

Hero Fiennes Tiffin_Dónal Finn_Zine Tseng_Natascha McElhone (Photo credit_ Dan Smith)

Dan Smith / Prime Video

**Who is in the Young Sherlock cast?**

Tiffin will lead the cast as the young Sherlock Holmes. Joining him are Firth as Sir Bucephalus Hodge, Dónal Finn as Moriarty, Ravi Aujla as Kishore Malik, Numan Acar as Esad, and Zine Tseng as Princess Gulun Shou-an.

Natashia McElhone will star as Sherlock’s mother, Cordelia Holmes, and his father, Silas Holmes, will be played by Joseph Finnes, who is also Tiffin’s real-life uncle.

**Who is behind Young Sherlock?**

Ritchie directed and executive-produced the series, marking his return to the universe after directing the 2009 film starring Downey as the detective. Young Sherlock will also reunite Ritchie and Tiffin, who starred in the director’s 2024 film The Ministry of Ungentlemanly Warfare.

“He’s so decisive and so good at what he does, it’s easy to trust him,” Tiffin told Collider about working with Ritchie. “From day one, he’d be saying ‘Do it like this, or do it like that.’ He could be quite direct with his direction, which I really like.”

The series is written and executive produced by Matthew Parkhill, with Harriet Creelman as co-executive producer. Also executive producing are Simon Kelton, Ivan Atkinson, Simon Maxwell, Dhana Gilbert, Colin Wilson, and Marc Resteghini.