The BBC have released the trailer for the upcoming finale of series 9 of Doctor Who. This is following the penultimate episode Heaven Sent that was a brave and gripping episode featuring an acting masterclass from Capaldi. The finale Hell Bent is seemingly set on the Timelords rediscovered home planet Gallifrey. The Doctor has been searching for Gallifrey since he saved it in the 50th Anniversary episode in 2013. Watch the trailer below and tune in on Saturday December 5 at 8pm on BBC One.