It seems like it’s been ages since the last time we saw consulting detective Sherlock Holmes (Benedict Cumberbatch) and his friend Dr. John Watson gallivanting about modern-day London solving mysteries. In truth, it was less than a year ago when BBC’s hit series Sherlock aired its last episode, the standalone Christmas special, ‘The Abominable Bride.’

At first the special appeared to have no connection to the previous season and the possible resurrection of Moriarty teased at the end of season 3. In the last scene of special, however, Sherlock realized the iconic villain did indeed die but left behind others to carry out his plans. Promos for season 4 have teased a return for Moriarty, but at this point it’s probably best to expect him only as a ghost haunting Sherlock, since it’s still not clear how he’ll fit into the upcoming season.

Instead a new, classic villain played by Toby Jones will be the focus of the new season, as Sherlock is reportedly about to take on ‘The Adventure of the Dying Detective.’ Three new episodes are set to air in early 2017, and they’re expected to be “myopically dark.” Now the titles of those episodes have been revealed on the series’ official Facebook page:

The titles of the first two episodes are ‘The Six Thatchers’ and ‘The Lying Detective,’ while the last one remains a mystery likely due to spoilers. ‘The Six Thatchers’ is probably a play on the Sherlock Holmes story ‘The Six Napoleons’ about a criminal destroying busts of Napoleon to find a hidden black pearl. This episode title is also very intriguing because it’s already been featured on Watson’s official blog (created for publicity by the BBC). The second episode title ‘The Lying Detective’ is again a reference to ‘The Dying Detective’ where Holmes pretends to be sickened with a deadly poison to catch a murderer named Culverton Smith.

So far these episode titles also match the clues of ‘Thatcher’ and ‘Smith’ previously given by showrunner Steven Moffat. Yet it’s the last clue of ‘Sherrinford’ and the mysterious last episode that is the most interesting. Sherrinford Holmes was one of the original names author Arthur Conan Doyle considered for his hero before settling on Sherlock Holmes. Other authors later used the name for Sherlock’s new, eldest brother, who was already referenced by Mycroft in season 3, episode 3, ‘His Last Vow.’ We’ll have to wait and see how Sherlock incorporates all these clues, characters and stories into the new season.

Sherlock season 4 will air in 2017 on BBC One and PBS.