This episode of Pretty Little Liars: Original Sin acts as the first season finale, where the main characters uncover secrets about their mothers' past while "A" manipulates events. The plot focuses on the "little liars" confronting the hidden truths about Angela Archie, while dealing with betrayal and mounting tension with their parents. You can find more details about this episode on IMDb and Decider . Chapter Eight: Bad Blood - Pretty Little Liars - IMDb