The Summer Finale of Pretty Little Liars Is Closer Than You Think

According to a press release from Freeform, "One of the PLLs learns a secret about her past that changes everything." We're trusting you to put two and two together here. If a member of the group has a dark secret, and if the identity of Mary Drake's other child is unknown . . . does that mean one of the liars could be Mary's child?!