A lonely teen builds an AI chatbot to get revenge on her ex–best friend and gets much more than she bargained for in this explosive first book in a new young adult thriller series from #1 bestselling author of the Pretty Little Liars books, Sara Shepard.

Sixteen-year-old Abby Ives has nothing left to lose. After a private photo gets sent around school, leaving her humiliated and exiled by nearly everyone, including her best friend, Abby starts her junior year ready for revenge. So she creates the perfect plan to get back at her ex–best friend, Olivia: coding an AI chatbot named Kitty. At first, it’s just a way to mess with Olivia and maybe get her in trouble at school. But then Olivia starts confiding real secrets. And sharing the bot with others.

Suddenly Abby finds herself the unexpected keeper of everyone’s dirtiest deeds and deepest fears. Who’s hooking up. Who’s cheating. Who’s struggling under their smile. Behind the screen, she is a force. Powerful. Untouchable in a way she’s never been. But she might actually be helping people in her school as Kitty too. Until someone tips off the bot about a sinister plot.

Unlike all the other secrets Abby has collected, this one is threatening—a plan that, if executed, means someone will end up dead. Can Abby stop that from happening without exposing herself as the mastermind behind Kitty? Or will her attempts turn the potential killer’s sights squarely on her instead?