Wikipedia
"Cyberwoman" is the fourth episode of the first series of the British science fiction television series Torchwood. Written by Chris Chibnall and directed by James Strong, the episode was first broadcast on the digital channel BBC Three on 5 November 2006, and later repeated on terrestrial channel BBC Two on 8 November.
In the episode, Ianto Jones ( Gareth David-Lloyd) is revealed to secretly house his girlfriend, Lisa Hallett ( Caroline Chikezie), a half-converted Cyberman, in the basement of the Torchwood Hub. Ianto wants to turn her into a human again, but by doing so her Cyberman influence takes control, and the rest of the team must stop her before she could become a threat to Earth. However, Ianto still believes she can be saved.
The episode was among the first pitched for the series, as creator Russell T Davies saw a potential to continue the story from the Doctor Who episodes " Army of Ghosts" and " Doomsday". Episode writer originally intended the episode to appear sometime midway through the series, but was ultimately brought forward to the fourth slot. It was filmed in the third production block. Because of the limited number of filming locations and cast members, it was among the cheapest episodes in the first series. It was seen by almost 1.4 million viewers after its original broadcast and received generally mixed reactions from critics, though the producers regard the episode as one of their favourites in the series.