Still shaken after her encounter with Bloody Rose, Mouse searches for the real Rose Waters while Imogen monitors Dr. Sullivan, Tabby works on a new project, Noa takes a break, and Faran faces an ultimate test.
Despite coming clean about 'A,' the friends find their troubles far from over, especially as the results of the group's clandestine blood drive push Tabby towards a new suspect.
As "A" doubles down, the friends must work quickly to uncover the link between Angela Waters' death, their mothers, and their mysterious foe - before it's too late.
The identities of the PLLs are leaked online and the girls rush to find out who is behind the anonymous calls as they keep Mouse's surprise party under wraps; the night of the party is near and Tabby uncovers a disturbing secret.
Desperate to keep her mother's house, Imogen throws a Halloween party to raise cash. Unfortunately, the presence of an unwanted house guest casts a shadow over the celebrations.
The friends attempt to get to the bottom of one mystery, while Imogen pursues answers to another. Then, a much needed girls' night prompts Sidney to confront her daughter about a long-held secret