The Little Liars go back into the basement at school on a quest to find more information, only to discover that all of Harold's stuff has been cleared. Hanna figures out that Lucas was involved, and when she confronts him, he warns her that Mona hasn't changed one bit. She's been blackmailing him to do her bidding.
Byron apologizes for accusing Aria and her friends for planting the bomb, but continues with his suspicious behavior. Ella recalls the night Ali disappeared, furthering Aria’s suspicions of Byron. Meanwhile, at the Brew, Meredith tells Aria that Byron met her the night Ali disappeared, and said he left her place to go meet with Ali.
Spencer is shocked when Mona joins the Academic Decathlon Team. And when she runs against Spencer for Team Caption, they have to have a quiz off, and Mona wins. Elsewhere, Paige struggles to move on after everything that's happened to her recently. After Emily tries to reassures her, they find their car tires slashed and chase a hooded stranger through the woods.