Neil Cross' popular Luther series - starring Idris Elba as DCI Luther - is sort of like the older, more cynical brother to Stephen Moffat's Sherlock. While the two shows go in different directions, both have a similar playfulness to them, both feel almost like event series (especially now that they only come out once every couple years), and both feature stars whose careers may yet outgrow their respective series.

Furthermore, both are in the process of filming "specials" for 2015. While the Sherlock episode is likely to be a Christmas special, Luther's is more of a two-part miniseries. Today, BBC America sent out a press release to publicize the start of filming for Luther, which included a set image featuring Idris Elba, some plot details, and a cast list that had one conspicuously missing name.

According to the release, titular hero John Luther will be "pitted against his most chilling adversary yet, haunted by the ghosts of his past and hell-bent on retribution" as he's "drawn into a terrifyingly complex case that pushes him closer to the edge than he's ever been." And that is surely saying something, considering Luther began as a series about a cop on the edge.

Luther Season 4 Idris Elba
Idris Elba on the set of the 'Luther' season 4 special

Said producer Elizabeth Kilgarriff:

"It’s very exciting to have Idris Elba back as DCI John Luther and to be in East London shooting the show’s fourth installment.  Neil Cross has pulled out all the stops to make this the biggest, scariest story yet and it’s a privilege to welcome such a glittering array of acting talent to our already stellar cast."

Creator Neil Cross will write the special, and Sam Miller (Fortitude) will direct it. In addition to Idris Elba, the cast will include Rose Leslie (Game of Thrones, Downton Abbey), Laura Haddock (Guardians of the Galaxy), Darren Boyd (Fortitude, Spy), John Heffernan (Ripper Street), and Patrick Malahide (The Paradise), with Michael Smiley and Dermot Crowley returning as Benny Silver and DSU Martin Schenk respectively.

Fans of Luther will almost certainly notice one glaring omission from that cast list: Ruth Wilson. Wilson has previously played Alice Morgan, the psycho killer and best friend/love interest (?) to John Luther. When last we saw Luther at the end of season 3, he was leaving behind his detectiving ways and setting off to who knows where with Alice, possibly to start up a romance.

Ruth Wilson and Idris Elba in Luther

Easily one of the best things about Luther is the strange and magnetic relationship between Luther and Alice. In fact, many fans would say that season 2 and season 3 suffered a bit because Alice's role had been so diminished. If indeed Ruth Wilson isn't returning for the season 4 special - which wouldn't be a huge surprise considering her Golden Globe-winning work on The Affair - it would be a major disappointment.

Then again, perhaps the producers are trying to keep Alice's role on the show a secret. While we shouldn't expect her to have a significant role, we shouldn't be shocked if she pops up at some point either.

What say you, Screen Ranters? Are you looking forward to new episodes of Luther? Are you hoping that Ruth Wilson will appear on the show as Alice Morgan? Drop us a line in the comments.

Luther will air sometime in 2015 on BBC and BBC America.