Winnie Campbell is sixteen and a burgeoning serial killer. Her father blames her for her mother's death, dotes on her little sister, and executes increasingly cruel punishments meant to humiliate Winnie. As the punishments morph into torture, she begins fantasizing about regaining some semblance of power, eventually working through her rage by killing small animals.
When her violent games escalate and she accidentally kills an infant while babysitting, Winnie gets a taste of a power she doesn't want to let go of. Her obsession with killing grows, and so does her fascination for Leigh, a girl that reminds her of her younger self.
Winnie wants to kill. She wants to die. She wants to be someone other than herself. And killing Leigh, a symbolic suicide, could be the key to her metamorphosis.