This last episode it was an invasion, but next week it's an inversion. BBC has released a trailer for next Saturday's episode of Doctor Who: "The Zygon Inversion."
Shapeshifting Zygons are everywhere in the UK, and there is no way of knowing who to trust. With UNIT neutralised, only the Doctor stands in their way. But how do you stop a war? And what can the Doctor do to save his friends?
Check out the sneak preview in the video below.
Doctor Who airs Saturdays at 9 p.m. ET on BBC America.