S4, E9: Paige (recurring guest star Lindsey Shaw) throws Emily a surprise birthday party with even more surprising guests - Jenna (recurring guest star Tammin Sursok) and Shana (recurring guest star Aeriel Miranda). But it's the actions of "A" at the party that lead to the biggest shock of all. Mona's selfless act provides Hanna and her mother with their first bit of good news, but it sends Mona down a familiar path. And Ezra gets some distressing news from Maggie (recurring guest star Larisa Oleynik) regarding her and Malcolm. Meanwhile, Aria and Jake (recurring guest star Ryan Guzman) continue trying to define their confusing relationship. And Emily meets with a world-class coach in a last-ditch effort to salvage her swimming career.