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.

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.

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.

"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,...

Even though the disappearance of Alison DiLaurentis has been solved, Spencer, Emily, Hanna, and Aria harbor other secrets which could interfere with their perfect lives, as they try to forget what happened to them in Jamaica last spring.

"Sutton Mercer had the perfect life, great friends, and a gorgeous boyfriend...until someone murdered her. Then the killer forced Sutton's long-lost twin sister, Emma, to pretend to be her. Now Sutton can only watch from beyond the grave as Emma frantically tries to figure out who killed her sister, and why. But when Sutton's body is discovered, Emma's time is up--and she becomes the number-one suspect herself."--Publisher's statement on Amazon.com....