Andrea Contos takes readers on a triumphant and terrifying journey, from fear and solitude to solidarity and vengeance. A complex and captivating thriller that kept me guessing at every turn. --Elle Cosimano, author of Finlay Donovan is Killing It

We were like fire, the four of us. Catching each other's sparks until the flames grew, spread, raged beyond our control.

We'll give them back the damage they left us with, burden them with the weight of our pain.

We may be temporarily broken, but we will leave them forever charred.

Ashes to ashes.

It wasn't the kidnapping that ruined Cass Adams's life. It was the letters that came after. The pink envelopes that appear in her car, her locker, her bedroom. Notes from the man she escaped, telling her that he's always there, always watching.

And that someday, he'll be back for her.

The police say there's nothing they can do, and Cass resigns herself to live in fear until she reconnects with three old friends-three girls ready to exact vengeance on those who wronged them.

But the deeper Cass digs, the more shocking the truth becomes, especially when she discovers that the person who ruined her life may be the only one who can save it.