When one of their tightly-knit group mysteriously disappears, four high school girls find their friendship difficult to maintain when they begin receiving taunting messages from someone who seems to know everything about their past and present secrets.

After high school juniors Spencer, Emily, Hanna, and Aria think they have seen Ali, their missing and presumed dead friend, they pursue clues from a mysterious stalker, trying to find out if she is still alive.

After their missing friend's body is found and another of their friends commits suicide, four former best friends live in fear of their secrets being exposed by someone who is stalking them via their cell phones.

After their friend who has been missing for more than three years turns up dead, four former best friends continue to receive frightening messages from someone who knows damaging secrets about them.

Watching from beyond the grave while her long-lost identical twin, Emma, assumes her identity, Sutton Mercer witnesses the discovery of a dark family secret and realizes that someone from Emma's past may be her own killer.

Struggling to return to normalcy after surviving Alison's attempt to kill them, Spencer, Aria, Emily and Hanna endure a series of disasters before realizing that they are being stalked by a new "A" who knows all of their secrets.

"It's springtime in Rosewood, but while everyone else is searching for the perfect prom dress, Hanna, Spencer, Emily, and Aria are on a different kind of hunt: They're looking for A...Hanna puts her campaign for prom queen on the back burner to volunteer at a burn clinic, where one of A's victims is recovering. Emily digs into Ali's past at the mental hospital with some very crazy consequences. Spencer contacts an amateur private eye to help her stalk...

When Emma Paxton steps into the life of her long-lost twin Sutton to solve her murder, she finds new suspects at every turn, while Sutton looks on from her afterlife.

While her late twin watches from the afterlife, Emma assumes Sutton's identity to solve the mystery of the latter's murder, an investigation that repeatedly implicates the handsome and mysterious Thayer.

"Ava, Caitlin, Mackenzie, Julie, and Parker are all driven to be perfect--no matter the cost. At first the girls think they have nothing in common, until they discover that they all hate the same person: handsome womanizer Nolan Hotchkiss, who's done things to hurt each of them. They come up with the perfect plan to murder Nolan--jokingly, of course. They'd never actually go through with it. But when Nolan turns up dead in the exact way they'd discussed,...