'Doctor Who' has for many years entertained sci-fi fans and pushed the boundaries of the genre like never before. This year it'll be returning for a Christmas special, as has become tradition, as the baton passes from one version of the Doctor to another. Directed and written by Rachel Talalay alongside outgoing series showrunner Steven Moffat, the final episode of the year will serve to tie up the Doctor's story as far as Peter Capaldi's version of the character goes, with Jodie Whittaker finally being properly introduced as the latest Doctor.

Peter Capaldi's set for his final 'Doctor Who' adventure this ChristmasPeter Capaldi's set for his final 'Doctor Who' adventure this Christmas

As the first female-bodied version of the Doctor, Whittaker has already faced a plethora of differing reactions following the casting announcement. The majority of fans however are excited to see exactly what she can bring to the role.

Now, the synopsis for this year's Christmas episode has been revealed, with the "end of an era" teased heavily.

The special episode's synopsis reads: "Two Doctors stranded in a forbidding snowscape, refusing to face regeneration. And a British army captain seemingly destined to die in the First World War but taken from the trenches to play his part in the Doctor’s story. This is the magical last chapter in the Twelfth Doctor’s epic adventure. He must face his past to decide his future. And the Doctor will realise the resilience of humanity, discovering hope in his darkest frozen moment. It’s the end of an era. But the Doctor’s journey is only just beginning."

What's even more exciting about this episode is the return of the First Doctor, albeit being a different actor with David Bradley in the role, following the passing of original First Doctor William Hartnell in 1975. It's going to be interesting to see exactly how much of the show is changed by having two Doctors 'in play' at the same time. We imagine there's a lot of chaos to come, and we can't wait to watch it all go down.

More: 'Doctor Who' Christmas Special Teaser Starring David Bradley Looks Epic

The Christmas special episode will air this December, with a new series of 'Doctor Who', led by Jodie Whittaker with Chris Chibnall as new showrunner, set to debut in 2018.