Before the Flood (in-universe)

Before the Flood was the fourth episode of the ninth series of Doctor Who. It followed Under the Lake and was succeeded by The Girl Who Died.

It featured the Doctor. Its synopsis mentioned "a fearsome alien warlord [setting] in motion a twisted plan". By 10 May 2020, the episode was available on BBC iPlayer along with the rest of series 9. (WC: The Zygon Isolation)