Who killed sixteen-year-old Ellie Stone? All anyone seems to know is that she was found dead at the edge of the river with a blue flower placed over each one of her eyes. No arrests have been made and nothing has been released about cause of death, only that it's been classified as a homicide. Now, months later, someone is sending letters to Ellie's best friend Tori, claiming they know more about the night she was killed. But who is it and just how much do they actually know?

Four students. Four perspectives. One of them is guilty of killing Ellie. Is it her best friend Tori? Piper, the outcast? Boy-genius Nick or his older brother Hayes? They're all keeping secrets. Some are covering up the truth. But who was really there that night? Who really knows it all?