S4, E8: Hanna comes up with a desperate plan to save her mother from a conviction and turns to the only person she thinks can help: Mona. Caleb tries to convince Hanna that Mona can't be trusted, causing Mona to prove her loyalty in the most unexpected way. And Spencer returns to an old haunt to investigate new evidence relating to Wilden and his surprising ties to another mysterious death. Meanwhile, recent machinations from "A" take their toll on Emily and her mom, driving Emily to reconnect with her old boss Zoe (guest star Rumer Willis – 90210) to look for an escape. And Aria relies on Jake (recurring guest star Ryan Guzman) to help her understand Mike's (recurring guest star Cody Allen Christian) new attitude, leaving them both confused about the nature of their relationship.