Aria remains suspicious of Byron when he mentions that the principal believes he knows who caused the fire. Emily, Hanna and Spencer sneak into the janitor's office again to look for Ali's diary. Instead, they encounter a mysterious figure who rushes out of the office before they can see his face and a fake diary with a note that reads, "Keep moving ladies. Nothing to see here. -A" Over coffee, the girls discuss recent events, including Aria's worries about Ezra and Byron. Mona comes over to them and confesses that she thinks the janitor is stalking her after she declined his unwanted sexual advances. Mona also tells them that he bribed the old janitor to take over his job so that he could be closer to her, and she thinks he is responsible for starting the fire. As expected, the girls doubt Mona's honesty and think there is more to her sob story. Hanna confronts Lucas who admits he was the one they saw in the janitor's office and that he was looking for something. Hanna offers to help him but he blows her off. Ella discusses the night of Ali's murder with Aria. She tells Aria that she and Byron attended a barbeque at Hollis but came home early where Ella passed out after drinking too much wine. At a meeting for the academic decathlon, Andrew Campbell informs the team that Mona will be joining them and running against Spencer for team captain. The team votes and after Andrew casts the last vote for Spencer, it is a tie. Spencer and Mona battle it out in a quiz-off with Mona winning and becoming the new team captain. When Hanna finds this out, she confronts Mona and exclaims that she knows she's still "A" and wants nothing to do with her. On the way to a swim team party, Paige has a panic attack. She and Emily pull over and Emily tries to comfort her. Paige confesses that she is scared and her fears are growing after recent shocking events. They go for a short walk and return to find one of the car tires slashed. Emily spots someone in a black hoodie hiding behind one of the nearby trees and chases the A Team member. She loses track of the hooded figure and Paige convinces her to return to the car. As they head back, the person in the hoodie is revealed to be Toby. Aria follows Meredith to a coffee shop after witnessing an argument between her and Byron at home. Meredith confesses to Aria that she caught Byron sneaking into Aria's room looking for something. Meredith also states that Byron met up with her but left her apartment to meet Ali on the night Ali was killed. When they return home, Aria begins feeling ill and Meredith brings her some tea. Meredith knows Aria has the page from Ali's diary proving Byron's affair. She asks Aria for it but Aria tells her she has already hidden it in safe place. Byron is seen leaving an office building late at night with Mona hot on his trail wearing a black hoodie. Mona lifts a cell phone to her ear and says, "he's leaving, I'll call you back." In the last scene, a member of the A Team runs into the woods and buries the Queen of Hearts mask and the baby mask under a pile of leaves and debris.