All is revealed as the ultimate endgame comes to light.
Convinced they know who A.D. is, the Liars gear up for a confrontation. Spencer, Hanna, and Caleb team up to investigate and discover new information about Charlotte’s death. Meanwhile, Mary Drake returns with a gift for Spencer and Alison.
As Detective Furey closes in on uncovering what happened to Archer Dunhill, the Liars team up to protect one of their own. Hanna continues to struggle with the idea that Lucas might be connected to A.D. even in the face of more evidence. Emily surprises Ali with a heartfelt gesture that is undone by A.D. machinations; and the Liars gain insight into where the idea for the game originated.
Emily butts heads with teenager Addison, who appears to be a new version of high school Ali, and who may be connected to a familiar foe. Spencer confronts her mother about keeping family secrets. Aria confides in Holden about her relationship with Ezra, while Spencer turns to Detective Furey for help. And Jenna stirs up even more trouble when she returns to Rosewood with some insight into Noel Kahn and recent events.
The Liars face off with their enemies in a chaotic fight that ends fatally. One of the PLLs learns a secret about her past that changes everything while another Liar discovers something about her future that could alter her course forever.
Still reeling from the trauma of Hanna's abduction and dark fate, the Liars must shift their focus to another one of their own. In order to protect Alison from Uber A's threats, the PLLs snap into action at a chance to rescue her from the hospital. However, in doing so, they make a deadly mistake that changes everything.
Based on the Pretty Little Liars series of young adult novels by Sara Shepard, the series follows the lives of four girls — Spencer, Hanna, Aria, and Emily — whose clique falls apart after the disappearance of their queen bee, Alison. One year later, they begin receiving messages from someone using the name "A" who threatens to expose their secrets — including long-hidden ones they thought only Alison knew.