Doctor: Peter Capaldi (Twelfth Doctor)
Companion: Jenna Coleman (Clara Oswald)
Michelle Gomez – Missy
Julian Bleach – Davros
Jami Reid-Quarrell – Colony Sarff
Joey Price – Boy
Nicholas Briggs – Voice of the Daleks
Barnaby Edwards – Dalek
Nicholas Pegg – Dalek
Directed by Hettie MacDonald
Written by Steven Moffat
Script editor David P Davis
Produced by Peter Bennett
Executive producer(s) Steven Moffat
Incidental music composer Murray Gold
Series Series 9
Length 2nd of 2-part story, 50 minutes
Originally broadcast 26 September 2015
Clara finds herself outside the Dalek city along with Missy, who had rigged their vortex manipulators to make them appear to have died from the Dalek attack, a trick she learned from the Doctor; however, the manipulators have been destroyed. They make their way in through a sewer, which contains a number of decaying and insane Dalek mutants. They discover a Dalek case, and Missy convinces Clara to enter it to help them re-enter the city. Once inside, Clara finds her words are translated into only "Exterminate" or "I am a Dalek". Once they access the city, Missy abandons Clara.
The Doctor does not believe Clara is dead. While confronting Davros and the Supreme Dalek, he is attacked by Colony Sarff and knocked unconscious. When he wakes, he is back with Davros, who is attached to numerous cables that provide life-support to him from every Dalek. Davros tempts the Doctor to kill all the Daleks using the cables, but the Doctor reveals he came to express compassion to Davros having abandoned him as a boy in the past. To give Davros enough life to see the sun rise, the Doctor provides some of his regeneration energy, but this travels through the cables to every Dalek, creating new hybrid forms.Missy appears and saves the Doctor while killing Sarff. The Doctor, aware of Davros' plan, notes even the insane Daleks will regenerate. They arise and attack the city, seeking revenge. The Doctor and Missy escape and run into Clara, still within the Dalek casing and unable to identify herself. Missy tries to tell the Doctor that Clara was killed, but the Doctor is able to see through her lies, particularly when the "Dalek" asks for mercy. He frees Clara and tells Missy to run. Missy is cornered by a number of Daleks, but states that she just had "a very clever idea".
The Doctor summons the TARDIS, which also had avoided destruction by its automated systems, using his new "sonic sunglasses". As the Dalek city is destroyed, he recalls why the Dalek casing allowed Clara to express a plea for mercy, and realises what he must do. They travel in the TARDIS to the battlefield that young Davros was caught in, and the Doctor uses a Dalek gun to eradacate the "handmines" and escort Davros away. The boy asks which side he fights for, and the Doctor replies it doesn't matter as long as there is mercy.