Aria, Emily, Hanna, and Spencer's stalker, A, wants to do more than ruin their lives, he wants to end them.

It's the end of seventh grade, and Alison DiLaurentis and her friends are the girls of Rosewood Day. Ali runs her clique with an iron fist, and she's got enough dirt on Hanna, Emily, Aria, and Spencer to keep them in line. But Ali's hiding a dark secret of her own, something so huge it would destroy everything if it ever got out... and in Rosewood, deadly secrets have deadly consequences...

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.

High school seniors Aria, Emily, Hanna, and Spencer have all done horrible things -- things that would put them behind bars if anyone ever found out. And their stalker 'A' knows everything. So far A has kept their secrets, using them to torture the girls. But now A's changed the game. Suddenly the girls are hauled in for questioning, and all their worlds begin to unravel. If A's plan succeeds, Rosewood's pretty little liars will be locked away for...