Sixteen-year-old Skye is done playing the knight in shining armor for her insufferable younger sister, Deirdre. Moving across the country seems like the perfect chance to start over. In their isolated new neighborhood, Skye manages to fit in, but Deirdre withdraws from everyone, becoming fixated on the swampy woods behind their house and building monstrous sculptures out of sticks and bones. Then Deirdre disappears. And when something awful comes scratching at Skye's window in the middle of the night, claiming she's the only one who can save Deirdre, Skye knows she will stop at nothing to bring her sister home.