In 1999, a group of friends is rocked by the sudden death of one of their own; twenty-two years later, their daughters are pushed together by a mysterious foe.

As Imogen and her newfound friends plot revenge against a mutual nemesis, Karen and her twin sister Kelly hatch an insidious plan of their own.

In the wake of Spirit Week's deadly aftermath, Imogen attempts to connect the dots between her former BFF, her deceased mother, and the mysterious "A;" as Sheriff Beasley closes in, the fate of the friend group hangs in the balance.

After their punishment comes to an end, the girls cement their friendship when Imogen needs them most; Noa finds herself in A's crosshairs.

Desperate to keep her mother's house, Imogen throws a Halloween party to raise cash, but the presence of an unwanted guest casts a shadow over the celebrations.

As Imogen and Tabby dig into the mystery surrounding Angela Waters, Faran deals with the scars of her past; after Shawn confronts Marjorie, Noa questions her relationship with her mother, while Mouse spots a familiar face on her first date.