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.

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