The episode starts with the Doctor stepping into a fairy circle, causing him to vanish and locking the Tardis. I’m not a huge fan of this season’s “magic is real” vibe, but so far it tracks.
A woman appears and follows Ruby around. She ends up in a pub where she asks about the fairy circle. After a long build up explaining just how serious the fairy circle is, it turns out no that’s just racist. Pretty funny, and it works with the magic theme. So how does the fairy circle actually work then? No fucking clue, they never explain it. As far as I can tell it just exists for this bit.
So this woman makes everyone near her hate Ruby. Everyone. Why? Who fucking knows. They never explain why. It just does. It leads up to a politician getting scared and ruining his career. Again pretty clever. But again no explanation is ever given as to how or why this happens.
Then Ruby dies. And when she dies she becomes the scary woman. Then she goes back in time. How? Why? No idea. It just happens and you gotta deal with it.
So apparently the Doctor stepping on a fairy circle that doesn’t do anything makes him vanish for no reason, creates an old copy of Ruby that follows her around for no reason, who scares everyone for no reason, then when Ruby dies undoes everything for no reason.
This. Makes. No. Sense.
Kate mentions this at the café as the distance where a person with 20/20 vision can’t make out any facial details anymore. But there never was mentioned any relation to the TARDIS perception filter.