The Zygon Inversion (in-universe)

The Zygon Inversion was the eighth episode of the ninth series of Doctor Who. It followed The Zygon Invasion and was succeeded by Sleep No More.

It featured The Doctor, Clara, Osgood and an individual resembling Kate Stewart. Its synopsis mentioned that "with UNIT neutralised, only the Doctor stands in the way..." By 10 May 2020, the episode was available on BBC iPlayer along with the rest of series 9. (WC: The Zygon Isolation)

Behind the scenes
This is a version of The Zygon Inversion that exists within the Doctor's universe.