A new "A" toys with the girls, using elevated stakes. Spencer and Hanna investigate this new foe, who turns one of Aria's past mistakes into ammunition and whose fearful actions have put Emily in a fragile state.

Caleb doesn't understand why Hanna is visiting Mona, and this tempts Hanna to tell him the truth. Meanwhile, Aria considers sharing details about her dad's dating life with her mom; Spencer seeks answers about Melissa; and Emily meets Maya's cousin.