Robertson returns, and inadvertently gives the mutant Dalek a chance to clone itself. The Doctor escapes from her alien prison with the help of an old friend, and returns to help.
Length 71 minutes
Jodie Whittaker | Bradley Walsh | Tosin Cole | Mandip Gill | John Barrowman | Chris Noth | Harriet Walter | Nathan Stewart-Jarrett | Nathan Armarkwei-Laryea | Helen Anderson | Nicholas Briggs | Barnaby Edwards | Nicholas Pegg | Sharon D. Clarke | Claire Ashton | Ruth Horrocks | Daniel Eghan | Steve Healey