adjust to his recent death. As part of his orientation, a meeting is arranged between Danny and a young civilian boy he accidentally killed while he was a soldier in Afghanistan. The boy runs off. Danny receives a call from Clara at 3W. The Doctor leaves with Chang to investigate further while Clara takes the call. Not wishing Clara to die, Danny does not convince her that he is really Danny, and tricks her into ending the call. Though Danny almost deletes his emotions, he hesitates when he sees the boy watching him. Missy instructs the skeletons to rise and begin draining the tanks. She kills Chang with a handheld device. The skeletons are revealed to be Cybermen. Missy tells the Doctor that dying minds are uploaded to the Nethersphere—a spherical Time Lord "hard drive"—where the emotions are deleted and the mind is downloaded into upgraded Cyberman bodies. The Doctor realises that Missy is not a droid, but a Time Lady. The Doctor races out of 3W and finds that it is inside St Paul's Cathedral in contemporary London. Missy reveals her identity as a female incarnation of the Master, having changed her name to fit her new gender. Clara is trapped in Chang's laboratory with another Cyberman. Production The read through for "Dark Water" took place on 12 June 2014. Filming began soon afterwards, on 16 June 2014. Locations for the episode included Cardiff, Pontypool and St. Paul's Cathedral. When filming the episode's climax, Peter Capaldi and Michelle Gomez mouthed their lines as the Doctor and Missy—recorded later using automated dialogue replacement—to hide the revelation from all spectators of the filming. To further ensure there was no leak, the climax was removed from all preview copies of the episode. Dan Martin calls the scene with the Cybermen emerging from St. Paul's Cathedral "a direct reference" to a similar shot from the 1968 serial The Invasion, and suspects the tomb-filled mausoleum may likewise reference the 1967 serial The Tomb of the Cybermen. Cast notes Sheila Reid made her second appearance as Clara's grandmother, having been introduced in "The Time of the Doctor"; she had previously appeared in Vengeance on Varos in 1985. Chris Addison appears as Seb. Broadcast and reception Preview release Scenes of "Dark Water" were removed from the DVD previews sent to reviewers, and a media blackout had been imposed on any plot details that were not released