Guy Ritchie’s Young Sherlock is Prime Video's upcoming thriller series starring Hero Fiennes Tiffin as Sir Arthur Conan Doyle’s legendary detective. The eight-part series is based on Andrew Lane's eponymous books, a bold reimagining of the formative years of Doyle's iconic sleuth.Set years before Sherlock Holmes becomes the sharp-eyed consulting detective audiences know so well, the series explores his formative experiences, methods of deduction and his earliest encounter with the figure who will one day define his greatest rivalry.While Young Sherlock will give an exciting peek into Holmes' university life, one of the most intriguing elements of the series is its decision to introduce Holmes’ future nemesis, James Moriarty (played by Dónal Finn), far earlier than expected. In Doyle’s stories and many popular adaptations, this adversary looms large as the embodiment of intellectual opposition, who challenges Holmes not through brute force but through equal mental strength.However, the series takes a bold new direction by reimagining Moriarty not as Sherlock’s infamous arch-nemesis (best known for their climactic showdown at the Reichenbach Falls), but as a friend who emerges as an unexpected ally, joining him as an unlikely sidekick on his very first case in the 1870s.More on this in our story.Young Sherlock will change the dynamics between Holmes and MoriartyEver wondered how Moriarty ended up becoming Holmes' mortal enemy? While many popular Sherlock adaptations have explored the characters' rivalry, readers are about to learn the origin story of this complicated relationship. Unlike previous adaptations, Young Sherlock will follow Holmes and Moriarty not as foes but as friends, two 19-year-old naive and unfiltered lads who develop an unlikely friendship at Oxford University.The recently released trailer for the Prime Video series follows Holmes as he enrolls at Oxford for his higher education and meets James Moriarty, his future nemesis. Further clips (in the teaser) hint at how Moriarty and Holmes develop a friendship and even partner up to solve a 'globe-trotting conspiracy' that takes them on a journey across the world. In one of the scenes from the trailer, Moriarty jokingly says to Holmes:''If you start wearing a hat like that, I will no longer be friends with you.''Sherlock fans are having a field day with this scene, jokingly calling Sherlock's hat the real villain in Sherlock and Moriarty's rivalry.Jokes aside, Young Sherlock is set to achieve what no other adaptation has dared to venture into before. While many adaptations have previously explored Holmes and Moriarty's rivalry, it would be interesting to witness their friendship and the reason behind their arch-rivalry.Young Sherlock showrunner teases a Holmes-Moriarty team-up View this post on Instagram Instagram PostIn an interview with Entertainment Weekly, showrunner Matthew Parkhill teased that Young Sherlock will explore the origin story of Holmes and Moriarty's complicated relationship. The characters started as friends but as seasoned Doyle readers will attest, they eventually transform into mortal enemies.Parkhill teased:"I always imagined what it would be like: How did they end up such mortal enemies? And I always thought, what if he had this incredible friendship?''He added:"You kind of get two origin stories for the price of one. Moriarty gets in hot water as well. And I think if these two hadn't met, it's sort of like a pinball and a pinball machine, if they hadn't met, Sherlock wouldn't have become the Sherlock that we know, and Moriarty wouldn't have become Moriarty."Parkhill's comments suggest Young Sherlock will closely follow the formative years of Doyle's sleuth, exploring how his early relationships and cases transformed him into the iconic detective from Baker Street. Additionally, the presence of Moriarty in Ritchie's world suggests the show will feature an unlikely sidekick for Holmes in Moriarty, who will replace the fan-favorite character of John Watson.Young Sherlock will debut on Prime Video on March 4, 2026.For the latest scoops on your favorite TV shows and movies, follow Soap Central.