The appeal of Sir Arthur Conan Doyle's brilliant detective Sherlock Holmes is so evergreen that in the last decade alone it has inspired two successful action movies and two modern TV adaptations. Of these, BBC's Sherlock has probably garnered the largest and most passionate fanbase, but due to lead actors Benedict Cumberbatch and Martin Freeman being in very high demand, the seasons tend to be quite short (consisting of three 90-minute episodes each) with long waits in between - plenty of time for hype and speculation to build up about what future stories might bring.
The most recent episode was ostensibly a one-off special set in the Victorian era, but it ended up providing a bridge between Sherlock's third and fourth seasons and offering a somewhat cryptic hint as to what role Sherlock's now-deceased arch-nemesis James Moriarty will play in episodes to come. Sherlock season 4 began filming last month and is set to air in early 2017, and now a distinguished name has joined the cast in a villain role.
Deadline reports that Toby Jones, whom Marvel fans might recognize as Nazi scientist and malevolent artificial intelligence Arnim Zola from the Captain America films, will appear in the second episode of Sherlock season 4. The show's co-creator, Steven Moffat, confirmed that Jones will be playing a character from the novels rather than one invented for the show, teasing that the actor will be "bringing to life one of Doyle’s finest villains." Jones is the first major guest star to be announced, and he will appear alongside a case of regulars that also includes Rupert Graves, Amanda Abbington, Louise Brealey, Una Stubbs, and Moffat's fellow showrunner Mark Gatiss.
There are plenty of possibilities as to who Jones might be playing. Many fans are hoping to see a version of Moriarty's accomplice Sebastian Moran in the fourth season, though since Moran is described as a tough-as-nails soldier, sportsman and expert marksman, Jones doesn't seem like quite the right fit. Besides, if Moran is in this series, perhaps executing Moriarty's commands beyond the grave, it's likely that he'll be in more than one episode. More likely, then, Jones is playing one of the many other devious antagonists from Doyle's stories.
If Sherlock's fourth season follows the same formula as the previous ones, it will presumably have individual cases in each episode alongside an ongoing mystery unfolding with regards to the season's main antagonist (whoever that might be). But even if Jones is only around for one episode, he's sure to provide an entertaining foil to Cumberbatch and Freeman's crime-solving duo.
Sherlock season 4 is expected to premiere on BBC One and BBC America in early 2017.