Shepard, Sara

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.

Best friends Spencer, Aria, Emily, and Hanna find themselves under suspicion when the mysterious stranger named A tries to blame one of the girls for the death of their friend Alison and threatens to reveal the girls' darkest secrets.

Emma is shocked to learn she has a twin sister, Sutton, but on the day the girls are supposed to meet, Sutton is killed, and Emma risks everything to slip into her twin's life and try to bring the killer to justice.

Seventeen-year-old Sutton Mercer watches from the afterlife as her long-lost twin sister, Emma Paxton, continues to pretend to be her in order to identify Sutton's killer.

Former best friends Emily, Aria, Hanna, and Spencer continue to live in fear as they struggle to keep hidden even more secrets and someone new begins stalking them via their cell phones.

While Emma continues to investigate her twin sister's death, Laurel is sneaking around with her sister's ex-boyfriend.

"Now that troubled Thayer Vega is back in town, Emma Paxton must struggle to figure out the relationship her twin has with him...and whether he may have been the one to kill her"--.

Hanna, Aria, Spencer, and Emily, having drifted apart after their best friend and leader, Alison, disappeared years earlier, find themselves in grave danger when they decide to pursue the truth about what happened to Alison.

"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.

Hanna, Spencer, Emily, and Aria are trying to move on and forget about their old friend Alison DiLaurentis and all the torture she put them through, but someone is trying to keep her spirit alive.