Sara Shepard

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.

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.

"Emily's been shipped off to Iowa to live with her überconservative cousins. Aria's boyfriend is behind bars--because of her. Spencer's afraid she was involved in Ali's murder. But Hanna's fate is far worse: she's clinging to life in the hospital because she knew too much. If these girls don't start listening to me, Hanna's going to look like the lucky one"--P. [4] of cover.

The four former best friends try to overcome their friend Ali's murder, but become alarmed when they receive text messages from the mysterious "A" and learn that their friend's accused killer has been released from jail on bail.

Poppy, Aster, Corrine, Natasha, and Rowan are the heiresses of the Saybrook's jewellery empire, a family business that is known for both its wealth, and a very old curse that leads to family members dying suddenly. When one of the 5 heiresses is killed, and an online gossip site publishes a statement "One Heiress Down, 4 more to go", an investigation is opened.

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.

In the weeks leading up to Ali's murder, Ali reveals her plots against Emily, Hanna, Aria, and Spencer, as well as a dark secret that has the potential to destroy everything.

"It's spring break, and the pretty little liars are trading in Rosewood for a cruise vacation. They want nothing more than to sail into the tropical sunset and leave their troubles behind for one blissful week. But where Emily, Aria, Spencer, and Hanna go, A goes, too. From scuba diving to tanning on the upper deck, A is there, soaking up all their new secrets. Emily is smooching a stowaway. Aria's treasure-hunting partner is a little too interested...

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.