The opening minutes of “The Zygon Invasion” prepare viewers for two important developments: the plot, via a brushing up on a past episode and the return of resident U.N.I.T. nerd Osgood (Ingrid Oliver). Story-wise, the first point is required since most of the episode’s narrative wouldn’t make sense without a review of 2013’s Doctor Who 50th anniversary special, in which the shape-shifting Zygons tried to take over the world. As for Osgood’s return, early promos left fans wondering how she could possibly still be alive since Missy killed her in the series eight finale, “Death in Heaven.”
Turns out Osgood is still alive because of a U.N.I.T. measure called “Operation Double,” by which 20 million Zygons were allowed to disperse across the planet and live as humans, among humans, in peace. The two Osgoods, or “sisters,” regularly record a video diary in order to keep track of the peace treaty and, should something go wrong, provide evidence of what happened to U.N.I.T. and the Doctor. Now that one of the sisters is dead, however, this fail-safe is no longer in place.
Oliver’s return to the Osgood role is a welcome one. Ever since the character’s first appearance in “The Day of the Doctor,” Tom Baker scarf and all, fans have identified with her. After all, it’s not that common to see someone onscreen who was as big a fan of the Doctor as everyone watching at home. So when Missy vaporized her at the end of the previous series, viewers were understandably shocked.
As wonderful as it is to see Osgood again, whether she’s the human or the Zygon sister remains to be seen. Not even the Doctor can figure it out, and Osgood refuses to tell him. “My sister and I were the living embodiment of the peace we made,” she tells him. “You want to know who I am, Doctor? I am the peace. I am human and Zygon.” This could mean any number of things, including yet another example of a hybrid being. But Osgood shrugs it off, as her revelation that the shape-shifters no longer require living human hosts to copy adds another level to the episode’s paranoia.
Paranoia is the name of the game in “The Zygon Invasion,” especially since a scene towards the end of the episode counters what Osgood says about Zygons no longer having to keep human hosts alive. So not only is the audience unable to tell which Osgood she is, but we’re also left in the dark as to whether or not she can be trusted. Oliver plays all these cards masterfully well against Peter Capaldi’s Doctor, which makes me hope she sticks around a bit longer in the series — whether or not she’s a Zygon, a villain or both.
