[NOTE: The following post contains rumors that, if true, could be considered MINOR SPOILERS for Doctor Who season 9]
The wait is almost over: the TARDIS will rematerialize for Doctor Who season 9 on September 19th and showrunner Steven Moffat has already teased a big, mad, and exciting slate of episodes - as the Doctor and Clara travel with reckless abandon through time and space. Season 8 spent a significant amount of time introducing Peter Capaldi's Doctor (Twelve) to the audience and Clara - as the Time Lord attempted to determine whether he was even a "good man" anymore. Similarly, after saying goodbye to her bow-tie wearing "boyfriend" (Matt Smith's Eleven), Clara was tasked with deciding whether she was still interested in journeying with this new Doctor.
The pair's personal struggles were mostly put to rest in the 2014 Christmas Special "The Last Christmas" - and, by the end of the Inception-like holiday misadventure, were poised to travel together for the foreseeable future. Showrunner Steven Moffat has indicated that Season 9 will feature The Doctor and Clara's "glory days" - but that doesn't mean that old foes and overarching franchise dangers won't return to wreck havoc on the friends.
We already know that Missy (aka The Master) will return for season 9 and that River Song is confirmed for a 2015 Christmas Special appearance, along with a mystery role for Game of Thrones actress Maisie Williams, but a new prologue episode for the premiere (check out the video up top) has many longtime Who viewers wondering if other fan-favorite series heroes and villains might also make an appearance.
In the clip, Clare Higgins returns as Ohila - the Sisterhood of Karn priestess who debuted in the 50th Anniversary Special prologue minisode "The Night of the Doctor." Attentive Who fans will remember that it was Ohila that warned the Eighth Doctor (Paul McGann) that he was the only person capable of ending the Time War - prompting the Time Lord to drink the Elixir of Life and regenerate into a "warrior" (John Hurt's "War Doctor").
This time around, Ohila is shown discussing an invitation the Doctor has received from an unnamed "he." Reading through the Doctor's lies (he claims to not like her, even though he does like her, and says he won't accept the invitation, even though his reasoning indicates he will), she appears reluctant to see the Time Lord confront his "enemy" - even stating that it will be the Doctor's "destruction."
Fans can certainly form their own opinion about the prologue - especially the identity of the unspoken "he" - as well as how the prequel minisode will setup the season 9 premiere. However, given that we know the Doctor is missing at the beginning of season 9, forcing Clara to team-up with Missy, it stands to reason that the prequel could have taken place long before the events depicted in the 2014 Christmas Special. If true, it's possible that The Doctor has been waylaid after visiting the mysterious "he" mentioned in the video - which some die-hard Whovians are already speculating to be Dalek creator Davros (who was rumored to appear in the two-part series opener).
Of course, another (more obvious) interpretation is that when Ohila refers to the "he," she's actually talking about The Master - possibly because the minisode takes place prior to Missy's official introduction to The Doctor at the end of season 8 or, simply, because Ohila has yet to adjust her gender signifier for a character that has been a male for the majority of her existence.
That all said, without knowing where the prologue fits into The Doctor's timeline, it's hard to determine which of the two archenemies (assuming the "he" isn't someone else entirely) that The Doctor and Ohila are discussing. After all, Missy reportedly helps locate the Doctor in the season 9 premier; so, if she is the he mentioned in the prequel minisode, Moffat will have needed to create a very timey-wimey storyline to make all the pieces fit into place.
Fortunately, fans won't have to wait too much longer to find out where the prologue slots into the larger season 9 arc - but, with two weeks left to go, there's still plenty of time to speculate and revel in pre-premiere discussion: what exactly does The Doctor hand Ohila in the prologue?
We'll keep you up to date as more season 9 details are released. While there isn't really any new information included, we've also embedded an interview with Higgins below - where she geeks-out about returning for another chapter of Doctor Who.
Doctor Who season 9 premieres September 19th, 2015 on BBC America.