The BBC have today released the synopsis for episode fourth episode of Series Nine of Doctor Who. Starring Peter Capaldi and Jenna Coleman the ninth series of the revived version of Doctor Who sees the intrepid time traveller and his companion seek out new worlds. Episode Four is written by veteran scribe Toby Whithouse and guest stars Colin McFarlane, Sophie Stone, Zaqi Ismail, Morven Christie, Arsher Ali, Steven Robertson, Paul Kaye, Neil Fingleton and Peter Serafinowicz. Episode Four of the new series will be broadcast on Saturday the 10th of October. Episode One can already be seen on the BBC iPlayer.

On a remote Army outpost, a fearsome alien warlord – the Fisher King – sets in motion a twisted plan to ensure his own survival. The ripples will be felt around the universe. Is this chain of events inevitable? And can the Doctor do the unthinkable?

With thanks to BBC Media