While the concept of "Pretty Little Liars: Original Sin" — a group of high-school-age girls being terrorized by a nameless, faceless assailant who goes by "A" — is the same as the original "Pretty Little Liars," it adds a lot of fresh, thrilling aspects to the plot that make it feel brand new. This version has far more slasher-horror vibes than the Freeform outing. And this time around, "A"'s motive for terrorizing the Liars has less to do with their own actions and everything to do with what their mothers did to a classmate named Angela Waters back in 1999. As their classmates are picked off one by one, the girls must figure out what their mothers did to make "A" seek revenge before they become the killer's next targets.
Watch "Pretty Little Liars: Original Sin" on HBO Max.
