Six months after "The Millwood Massacre," the girls eagerly await a verdict in A's trial – as well as a much-needed break – until a failed exam condemns them to a fate worse than death: summer school.

Haunted by increasingly disturbing hallucinations, Imogen attempts to forge a new identity outside of Millwood. As summer kicks off, Noa reconnects with an old friend, Tabby meets her movie-buff match, Faran gets a job as Millwood Community Pool's only female lifeguard, and Mouse is threatened by an unknown entity.

When their identities are revealed online, the PLLs scramble to figure out who is behind a series of anonymous calls – and keep Mouse's surprise birthday party under wraps. As the night of the party nears, Tabby uncovers an unsettling secret in Christian's basement, Imogen calls out her new coworker, Noa clashes with Jen, and Faran finally spills her secret.

Still shaken from her encounter with Bloody Rose, Mouse searches for the real Rose Waters. Meanwhile, Imogen keeps tabs on Dr. Sullivan, Tabby works on a new short, Noa takes a much-needed day off, and Faran’s strength is put to the ultimate test.

A disturbing discovery causes the PLLs to doubt Dr. Sullivan. Meanwhile, during Tabby's movie marathon, Noa is forced to make a brutal decision.

After discovering that Kelly's church is using her former home, Imogen springs into action, while Mouse and Ash plan a Pride pool party in protest.

Still shaken from Hell House, Imogen learns about Dr. Sullivan's secret ties to A, while the PLLs set out to uncover Bloody Rose's identity.

The PLLs take a final stab at their list of suspects, and through a harrowing night will discover the identity of Bloody Rose Waters once and for all.