A.D. theory!

Listen to this, we know that Spencer is Mary’s child, but this show is insane, so what if… Spencer have a twin, like her mother, and that twin is Avery, the friend of Sara Harvey! We never see her face, and her friends (Clair and the other girl) never saw Spencer. And she goes for the name Avery Drake(A.D.) And Avery is the one we see with Hanna in 7x01, it wasn’t a dream, it was Avery! And that explain why Sara was in the middle of all this, it’s her best friend.