Plot summary
The police test the gun Hanna was caught with to determine if it was a match for the gun that killed Wilden. Shana replaces Emily on the swim team. Mike's friend, Connor, kisses Aria after she helps him with an English paper. When rumors fly, Aria confronts Connor who reveals that everyone knows about her and Ezra. Ezra comes to her rescue and silences Connor. Mona reveals to Aria and Emily that Toby took the RV to "A" and that Spencer knew about it. Clues from the sorority house send Spencer and Toby to Ravenswood where they find the ex-house mother Mrs. Grunwald who provides no help.
Additionally, they spot Shana in Ravenswood getting into Jenna's car. When the gun tests positive as a match for the one that killed Wilden, the police arrest Ashley. The police also bring Emily in for questioning when a mysterious video showing someone in a red coat wearing an Emily mask reveals that Emily may be guilty of something. ' A' ending: 'A' hot-wires a car while wearing an Emily mask.
Credits
Adapted from Wikipedia contributors, Pretty Little Liars season 4. HTML formatting and reference markers removed.